trypsinogen and Cystic-Fibrosis

Cystic fibrosis (CF) is one of the most commonly diagnosed genetic disorders. Clinical characteristics include progressive obstructive lung disease, sinusitis, exocrine pancreatic insufficiency leading to malabsorption and malnutrition, liver and pancreatic dysfunction, and male infertility. Although CF is a life-shortening disease, survival has continued to improve to a median age of 46.2 years due to earlier diagnosis through routine newborn screening, promulgation of evidence-based guidelines to optimize nutritional and pulmonary health, and the development of CF-specific interdisciplinary care centers. Future improvements in health and quality of life for individuals with CF are likely with the recent development of mutation-specific modulator therapies. In this review, we will cover the current understanding of the disease manifestations, diagnosis, and management as well as common complications seen in individuals with CF.

Topics: Bone Density; Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Humans; Infant; Infant, Newborn; Liver Diseases; Lung; Lung Transplantation; Male; Respiratory Tract Infections; Trypsinogen; Vitamins

Exocrine pancreatic insufficiency in children can lead to lifelong complications related to malnutrition and poor growth. The clinical presentation can be subtle in the early stages of insufficiency as the large functional capacity of the pancreas is gradually lost. The pediatrician plays a crucial role in the early identification of these children to ensure a timely referral so that a diagnosis can be made and therapy initiated. Early nutritional therapy allows for prevention and correction of deficiencies, which leads to improved outcomes and survival. When insufficiency is suspected, the workup should start with an indirect test of exocrine pancreatic function, such as fecal elastase, to establish the diagnosis. Once a diagnosis is established, further testing to delineate the etiology should be pursued, with cystic fibrosis being high on the differential list and assessed for with a sweat test. Assessment of anthropometry at every visit is key, as is monitoring of laboratory parameters and physical examination findings that are suggestive of malabsorption and malnutrition. The mainstay of management is administration of exogenous pancreatic enzymes to facilitate digestion and absorption. [Pediatr Ann. 2019;48(11):e441-e447.].

Topics: Acyl-CoA Dehydrogenase, Long-Chain; Anus, Imperforate; Child; Child Nutrition Disorders; Chymotrypsin; Congenital Bone Marrow Failure Syndromes; Cystic Fibrosis; Dietary Fats; Ectodermal Dysplasia; Enzyme Replacement Therapy; Exocrine Pancreatic Insufficiency; Feces; Growth Disorders; Hearing Loss, Sensorineural; Humans; Hypothyroidism; Intellectual Disability; Lipid Metabolism, Inborn Errors; Mitochondrial Diseases; Muscular Diseases; Nose; Nutrition Assessment; Pancreas; Pancreatic Diseases; Pancreatic Elastase; Pancreatic Function Tests; Pancreatitis, Chronic; Shwachman-Diamond Syndrome; Steatorrhea; Trypsinogen

Since the late 1970s when the potential of the immunoreactive trypsinogen assay for early identification of infants with cystic fibrosis was first recognised, the performance of newborn blood spot screening (NBS) has been continually assessed and its use has gradually expanded. NBS for cystic fibrosis is a cost-effective strategy and, if standards of care are fully implemented and robust management pathways are in place, has a positive effect on clinical outcomes. In the past decade, NBS has undergone rapid expansion and an unprecedented number of infants with cystic fibrosis have access to early diagnosis and care. Cystic fibrosis NBS has now moved on from the development phase and is entering an era of consolidation. In the future, research should focus on the rationalisation and optimisation of existing programmes, with particular attention to bioethical implications such as unwanted detection of carriers and inconclusive diagnoses.

Topics: Cost-Benefit Analysis; Cystic Fibrosis; Early Diagnosis; Female; Humans; Immunoenzyme Techniques; Infant, Newborn; Male; Neonatal Screening; Trypsinogen

Newborn screening for cystic fibrosis (CF) is now universal in the US and many other countries. The rapid expansion of screening has resulted in numerous publications identifying new challenges for healthcare providers. This review provides an overview of these publications and includes ideas on managing these challenges.. Most CF newborn screening algorithms involve DNA mutation analysis. As screening has expanded, new challenges have been identified related to carrier detection and inconclusive diagnoses. Early descriptions of infants with CF-related metabolic syndrome (CRMS) indicate that the natural history of this condition cannot be predicted. Early identification has also provided an opportunity to better understand the pathophysiology of CF. However, few studies have been conducted in infants with CF to determine optimal therapy and recommendations are largely anecdotal.. Newborn screening provides an opportunity to identify and begin treatment early in individuals with CF. Whereas a single, optimal approach to screening does not exist, all programs can benefit from new findings regarding sweat testing, carrier detection, early pathophysiology, and clinical outcomes.

Topics: Biomarkers; Cystic Fibrosis; False Positive Reactions; Genetic Carrier Screening; Humans; Infant, Newborn; Neonatal Screening; Sweat; Trypsinogen

Cystic fibrosis is the most common lethal genetic disease in Caucasians, manifesting as progressive lung dysfunction, pancreatic insufficiency, and intestinal disease. CF was traditionally diagnosed clinically, either because of a family history or occurrence of meconium ileus, or as a result of intestinal malabsorption and chronic pulmonary disease. In 1979, it was discovered that immunoreactive trypsinogen was increased in neonatal dried-blood specimens on Guthrie cards, making it possible to screen neonates. During the past decades, survival rates of patients with CF have improved significantly (see Figure 5). To continue this progress, universal newborn screening has been implemented in many states as an addition to the arsenal of therapies and strategies to improve survival. National newborn-screening programs to identify CF patients after birth have been adopted for a number of years in Europe, Australia, and Canada. As expected, many benefits have been seen due to the early identification of CF patients, including improved survival, better lung function and growth with less intensive therapy, and reduced cost of therapy. To date, 37 states in the United States have adopted similar programs, in the hopes of improving CF outcomes. This welcome trend should help improve the lives of CF patients living in America.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Exocrine Pancreatic Insufficiency; Female; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Pregnancy; Prenatal Diagnosis; Sodium Chloride; Sweat; Trypsinogen; United States; White People

Hereditary chronic pancreatitis (HCP) is a very rare form of early onset chronic pancreatitis. With the exception of the young age at diagnosis and a slower progression, the clinical course, morphological features and laboratory findings of HCP do not differ from those of patients with alcoholic chronic pancreatitis. As well, diagnostic criteria and treatment of HCP resemble that of chronic pancreatitis of other causes. The clinical presentation is highly variable and includes chronic abdominal pain, impairment of endocrine and exocrine pancreatic function, nausea and vomiting, maldigestion, diabetes, pseudocysts, bile duct and duodenal obstruction, and rarely pancreatic cancer. Fortunately, most patients have a mild disease. Mutations in the PRSS1 gene, encoding cationic trypsinogen, play a causative role in chronic pancreatitis. It has been shown that the PRSS1 mutations increase autocatalytic conversion of trypsinogen to active trypsin, and thus probably cause premature, intrapancreatic trypsinogen activation disturbing the intrapancreatic balance of proteases and their inhibitors. Other genes, such as the anionic trypsinogen (PRSS2), the serine protease inhibitor, Kazal type 1 (SPINK1) and the cystic fibrosis transmembrane conductance regulator (CFTR) have been found to be associated with chronic pancreatitis (idiopathic and hereditary) as well. Genetic testing should only be performed in carefully selected patients by direct DNA sequencing and antenatal diagnosis should not be encouraged. Treatment focuses on enzyme and nutritional supplementation, pain management, pancreatic diabetes, and local organ complications, such as pseudocysts, bile duct or duodenal obstruction. The disease course and prognosis of patients with HCP is unpredictable. Pancreatic cancer risk is elevated. Therefore, HCP patients should strongly avoid environmental risk factors for pancreatic cancer.

Topics: Adult; Animals; Carrier Proteins; Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Databases, Genetic; Diagnosis, Differential; Disease Models, Animal; Genetic Counseling; Genetic Predisposition to Disease; Genetic Testing; Humans; Mice; Mutation; Pancreatic Neoplasms; Pancreaticojejunostomy; Pancreatitis, Chronic; Prognosis; Rats; Risk Factors; Trypsin; Trypsin Inhibitor, Kazal Pancreatic; Trypsinogen

Newborn screening for cystic fibrosis (CF) was considered over 3 decades ago in 1970; however, the technology did not exist then for an accurate neonatal screening test. With the development of immunoreactive trypsinogen analysis, alone or coupled with DNA mutation analysis, the means were developed for CF newborn screening. Studies have demonstrated benefits of newborn screening in the areas of nutrition, cognitive function, pulmonary function, and survival.

Topics: Clinical Trials as Topic; Cognition Disorders; Cost-Benefit Analysis; Cystic Fibrosis; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Nutritional Support; Respiratory Function Tests; Survival Rate; Trypsinogen

Topics: Biomarkers; Cystic Fibrosis; Genetic Testing; Humans; Infant, Newborn; Mutation; Neonatal Screening; Trypsinogen; United Kingdom

Newborn screening for cystic fibrosis has been used in Australia and New Zealand for over 20 years. In that time, considerable experience has been developed regarding the early diagnosis of cystic fibrosis after newborn screening. To date, there has not been a consensus on the process of screening and clinical evaluation leading to the diagnosis of cystic fibrosis in infants, many of whom are not symptomatic at time of notification of the screening result. The aim of this paper is to provide some consensus on the important issues of a cystic fibrosis diagnosis arising from newborn screening, based on the experience gained in Australia and New Zealand over the last 20 years.

Topics: Australasia; Australia; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Neonatal Screening; New Zealand; Sweat; Trypsinogen

In November 2003, CDC and the Cystic Fibrosis Foundation cosponsored a workshop to review the benefits and risks associated with newborn screening for cystic fibrosis (CF). This report describes new research findings and outlines the recommendations of the workshop. The peer-reviewed evidence presented at the workshop supports the clinical utility of newborn screening for CF. Demonstrated long-term benefits from early nutritional treatment as a result of newborn screening for CF include improved growth and, in one study, cognitive development. Other benefits might include reduced hospitalizations and improved survival. Mixed evidence has been reported for pulmonary outcomes. Newborn screening in the United States is associated with diagnosis of CF a median of 1 year earlier than symptomatic detection, which might reduce the expense and anxiety associated with workup for failure to thrive or other symptoms. Certain psychosocial risks for carrier children and their families (e.g., anxiety and misunderstanding) are associated with newborn screening. Exposure of young children to infectious agents through person-to-person transmission in clinical settings, although not an inherent risk of newborn screening, is a potential cause of harm from early detection. Involving specialists in CF care and infection control, genetic counseling, and communication can minimize these potential harms. Although screening decisions depend on a state's individual resources and priorities, on the basis of evidence of moderate benefits and low risk of harm, CDC believes that newborn screening for CF is justified. States should consider the magnitude of benefits and costs and the need to minimize risks through careful planning and implementation, including ongoing collection and evaluation of outcome data.

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Health Education; Humans; Infant, Newborn; Infection Control; Neonatal Screening; Prenatal Diagnosis; Risk; Trypsinogen; United States

Pancreatitis has a proven genetic basis in a minority of patients.. Review of the literature on genetics of pancreatitis.. Ever since the discovery that in most patients with hereditary pancreatitis a mutation in the gene encoding for cationic trypsinogen (R122H) was found that results in a gain of trypsin function', many other mutations in the cationic trypsinogen gene, as well as in the gene encoding for pancreatic secretory trypsin inhibitor, have been found in patients with chronic pancreatitis. Furthermore, mutations in other genes, like the mucoviscoidosis-gene encoding for a chloride channel, and in genes encoding for enzymes involved in the metabolism of ethanol, have been linked to chronic pancreatitis. This article reviews the highlights that have been achieved in this field of pancreatic research.. Recent data suggest that genetics may play a role in the pathogenesis of pancreatitis.

Topics: Chronic Disease; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Mutation; Pancreatitis; Trypsin; Trypsinogen

Topics: Cystic Fibrosis; Humans; Pancreatitis; Point Mutation; Trypsin; Trypsin Inhibitor, Kazal Pancreatic; Trypsinogen

The recent genetic discoveries in CP support the hypothesis that inappropriate intrapancreatic activation of zymogens by trypsin results in autodigestion and pancreatitis. Two different protective mechanisms prevent activation of the pancreatic digestive enzyme cascade. First, SPINK1 inhibits up to 20% of potential trypsin activity and, second, trypsin itself activates trypsin-like enzymes readily degrading trypsinogen and other zymogens. Pancreatitis may therefore be the result of an imbalance between proteases and their inhibitors within the pancreatic parenchyma. The discovery of PRSS1 mutations in families with CP was the first breakthrough in the understanding of the underlying genetic mechanisms. Enhanced trypsinogen activation may be the common initiating step in pancreatitis caused by these mutations. The discovery of SPINK1 mutations underlines the importance of the protease inhibitor system in the pathogenesis of CP. Thus, gain-of-function in the cationic trypsinogen resulting in an enhanced autoactivation, or loss-of-function mutations in SPINK1 leading to decreased inhibitory capacity, may similarly disturb the delicate intrapancreatic balance of proteases and their inhibitors. The recent findings of SPINK1, CFTR, and PRSS1 mutations in CP patients without a family history have challenged the concept of idiopathic CP as a non-genetic disorder and the differentiation between HP and ICP. There is a clear mode of autosomal dominant inheritance for some mutations (R122H, N291, possibly MIT), whereas the inheritance pattern (autosomal recessive, complex, or modifying) of other mutations (A16V, N34S) is controverted or unknown. The lack of mutations in the above-mentioned genes in many patients suggests that CP may also be caused by genetic alterations in yet unidentified genes. Evaluation of CP patients without an obvious predisposing factor, e.g. alcohol abuse, should include genetic testing even in the absence of a family history of pancreatitis. Finally, identification of further disease-causing genes will create a better understanding of pathogenesis and may help to develop specific preventive and therapeutic strategies.

Topics: Chronic Disease; Cystic Fibrosis; Genetic Predisposition to Disease; Genetic Testing; Genotype; Humans; Mutation; Pancreatitis; Polymorphism, Genetic; Trypsin; Trypsin Inhibitor, Kazal Pancreatic; Trypsinogen

Cystic fibrosis (CF), the most common lethal genetic disease affecting Caucasians, is a multi-system illness, most frequently characterized by childhood chronic obstructive pulmonary disease, pancreatic exocrine insufficiency, and abnormal sweat electrolyte concentrations. The diagnosis of CF is based on a combination of the above clinical findings and/or a positive family history of the illness in conjunction with an abnormal sweat test. The quantitative pilocarpine iontophoresis test is the sole acceptable method for diagnostic confirmation of the clinical suspicion of CF. A recent advance in the diagnosis of CF has been in the development of methods for neonatal detection. The immunoreactive trypsinogen (IRT) detection test is practical, adaptable to large scale screening of dried neonatal blood spots, relatively inexpensive, and promising for the detection of newborns with CF who have pancreatic insufficiency. However, the reliability and validity of this method have not yet been adequately established. Major advances in the treatment of patients with CF have emerged in the last decades, particularly in supportive pulmonary and nutritional care.

Topics: Adolescent; Anti-Bacterial Agents; Child; Child, Preschool; Chlorides; Cystic Fibrosis; Humans; Infant; Infant, Newborn; Mass Screening; Pancreatitis; Pilocarpine; Respiratory Tract Infections; Sweat; Trypsinogen

Topics: Amino Acid Metabolism, Inborn Errors; Amylases; Child, Preschool; Cholecystokinin; Cystic Fibrosis; Dicloxacillin; Humans; Infant; Infant, Newborn; Kidney Diseases; Lipase; Lipid Metabolism, Inborn Errors; Pancreas; Pancreatic Cyst; Pancreatic Diseases; Pancreatic Extracts; Prognosis; Secretin; Triglycerides; Trypsinogen; Uric Acid

Newborn screening for cystic fibrosis (CF) is included in many routine programmes but current strategies have considerable drawbacks, such as false-positive tests, equivocal diagnosis and detection of carriers.. To assess the test performance of two newborn screening strategies for CF.. In 2008 and 2009, CF screening was added to the routine screening programme as a prospective study in part of The Netherlands.. Two strategies were performed in all newborns. In the first strategy, concentrations of immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP) were measured. In the second method, samples with IRT ≥60 μg/litre were analysed for 36 CFTR mutations, followed by sequencing when a single mutation was detected. Tests were positive only with two identified CFTR mutations.. Sensitivity, specificity and positive predictive value (PPV) of both screening strategies.. 145,499 infants were screened. The IRT/PAP approach showed a sensitivity of 95.0%, a specificity of 99.897% and a PPV of 12.3%. Test properties for the IRT/DNA/sequencing strategy were respectively 100%, 100% and 64.9%. Combining both strategies (IRT/PAP/DNA/sequencing) led to a sensitivity of 95.0%, a specificity of 100% and a PPV of 87.5%.. In conclusion, all strategies performed well. Although there was no statistically significant difference in test performance, the IRT/DNA/sequencing strategy detected one infant that was missed by IRT/PAP (/DNA/sequencing). IRT/PAP may be the optimal choice if the use of DNA technology must be avoided. If identification of carriers and equivocal diagnosis is considered an important disadvantage, IRT/PAP/DNA/sequencing may be the best choice.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Clinical Protocols; Cystic Fibrosis; Female; Humans; Infant, Newborn; Lectins, C-Type; Male; Mutation; Neonatal Screening; Netherlands; Pancreatitis-Associated Proteins; Predictive Value of Tests; Prospective Studies; Sensitivity and Specificity; Trypsinogen

Cystic fibrosis (CF) is a life-threatening disease for which early diagnosis following newborn screening (NBS) improves the prognosis. We performed a prospective assessment of the immunoreactive trypsinogen (IRT)/DNA/IRT protocol currently in use nationwide, versus the IRT/pancreatitis-associated protein (PAP) and IRT/PAP/DNA CF NBS protocols. Dried blood spots (DBS) from 106,522 Czech newborns were examined for IRT concentrations. In the IRT/DNA/IRT protocol, DNA-testing was performed for IRT ≥ 65 ng/mL. Newborns with IRT ≥ 200 ng/mL and no detected cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations were recalled for a repeat IRT. In the same group of newborns, for both parallel protocols, PAP was measured in DBS with IRT ≥ 50 ng/mL. In PAP-positive newborns (i.e., ≥1.8 if IRT 50-99.9 or ≥1.0 if IRT ≥ 100, all in ng/mL), DNA-testing followed as part of the IRT/PAP/DNA protocol. Newborns with at least one CFTR mutation in the IRT/DNA/IRT and IRT/PAP/DNA protocols; a positive PAP in IRT/PAP; or a high repeat IRT in IRT/DNA/IRT were referred for sweat testing.. the combined results of the utilized protocols led to the detection of 21 CF patients, 19 of which were identified using the IRT/DNA/IRT protocol, 16 using IRT/PAP, and 15 using IRT/PAP/DNA. Decreased cut-offs for PAP within the IRT/PAP protocol would lead to higher sensitivity but would increase false positives. Within the IRT/PAP/DNA protocol, decreased PAP cut-offs would result in high sensitivity, an acceptable number of false positives, and would reduce the number of DNA analyses. Thus, we concluded that the IRT/PAP/DNA protocol would represent the most suitable protocol in our conditions.

Topics: Antigens, Neoplasm; Biomarkers; Biomarkers, Tumor; Clinical Protocols; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Czech Republic; DNA Mutational Analysis; Dried Blood Spot Testing; False Negative Reactions; False Positive Reactions; Genetic Markers; Humans; Infant, Newborn; Lectins, C-Type; Neonatal Screening; Pancreatitis-Associated Proteins; Prospective Studies; Sensitivity and Specificity; Sweat; Trypsinogen

To evaluate the performance of a strategy in which, after immunoreactive trypsinogen (IRT) determination, genetic analysis is replaced by a biological test, the pancreatitis-associated protein (PAP) enzyme-linked immunosorbent assay (ELISA).. The French newborn screening program includes cystic fibrosis (CF) screening by the IRT/CFTR mutation strategy. PAP was assayed on screening cards, in parallel with IRT, in all newborns from 5 French regions (n = 204,749). Analysis of PAP values in CF and non-CF newborns with elevated IRT allowed direct comparison between the current strategy and the proposed IRT/PAP strategy.. A protocol in which newborns with IRT >50 ng/mL and PAP >1.8 ng/mL and those with IRT >100 ng/mL and PAP >1.0 ng/mL are directly recalled for sweat testing would have the same performance as the IRT/CFTR mutation strategy.. The IRT/PAP strategy is an alternative for CF newborn screening, which avoids the drawbacks of genetic analysis and is cheaper and easier to implement than the current IRT/CFTR mutation strategy.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; France; Humans; Infant, Newborn; Lectins, C-Type; Neonatal Screening; Pancreatitis-Associated Proteins; Sensitivity and Specificity; Sweat Glands; Trypsinogen

Patients who have cystic fibrosis (CF) and experience delayed diagnosis by traditional methods have greater nutritional insult compared with peers diagnosed via neonatal screening. The objective of this study was to evaluate cognitive function in children with CF and the influence of both early diagnosis through neonatal screening and the potential effect of early malnutrition.. Cognitive assessment data were obtained for 89 CF patients (aged 7.3-17 years) during routine clinic visits. Patients had been enrolled in either the screened (N = 42) or traditional diagnosis (control) group (N = 47) of the Wisconsin CF Neonatal Screening Project. The Test of Cognitive Skills, Second Edition was administered to generate the Cognitive Skills Index (CSI) and cognitive factor scores (Verbal, Nonverbal, and Memory).. Cognitive scores in the overall study population were similar to normative data (CSI mean [standard deviation]: 102.5 [16.6]; 95% confidence interval: 99.1-105.9). The mean (standard deviation) CSI scores for the screened and control groups were 104.4 (14.4) and 99.8 (18.5), respectively. Significantly lower cognitive scores correlated with indicators of malnutrition and unfavorable family factors such as single parents, lower socioeconomic status, and less parental education. Our analyses revealed lower cognitive scores in patients with low plasma alpha-tocopherol (alpha-T) levels at diagnosis. In addition, patients in the control group who also had vitamin E deficiency at diagnosis (alpha-T < 300 microg/dl) showed significantly lower CSI scores in comparison with alpha-T-sufficient control subjects and both deficient and sufficient alpha-T subsets of screened patients.. Results suggest that prevention of prolonged malnutrition by early diagnosis and nutritional therapy, particularly minimizing the duration of vitamin E deficiency, is associated with better cognitive functioning in children with CF.

Topics: Adolescent; Child; Cognition; Cystic Fibrosis; Diagnostic Errors; Female; Follow-Up Studies; Humans; Infant Nutrition Disorders; Infant, Newborn; Intelligence Tests; Male; Neonatal Screening; Nutritional Status; Regression Analysis; Trypsinogen

Many patients with cystic fibrosis are malnourished at the time of diagnosis. Whether newborn screening and early treatment may prevent the development of a nutritional deficiency is not known.. We compared the nutritional status of patients with cystic fibrosis identified by neonatal screening or by standard diagnostic methods. A total of 650,341 newborn infants were screened by measuring immunoreactive trypsinogen on dried blood spots (from April 1985 through June 1991) or by combining the trypsinogen test with DNA analysis (from July 1991 through June 1994). Of 325,171 infants assigned to an early-diagnosis group, cystic fibrosis was diagnosed in 74 infants, including 5 with negative screening tests. Excluding infants with meconium ileus, we evaluated nutritional status for up to 10 years by anthropometric and biochemical methods in 56 of the infants who received an early diagnosis and in 40 of the infants in whom the diagnosis was made by standard methods (the control group). Pancreatic insufficiency was managed with nutritional interventions that included high-calorie diets, pancreatic-enzyme therapy, and fat-soluble vitamin supplements.. The diagnosis of cystic fibrosis was confirmed by a positive sweat test at a younger age in the early-diagnosis group than in the control group (mean age, 12 vs. 72 weeks). At the time of diagnosis, the early-diagnosis group had significantly higher height and weight percentiles and a higher head-circumference percentile (52nd, vs. 32nd in the control group; P=0.003). The early-diagnosis group also had significantly higher anthropometric indexes during the follow-up period, especially the children with pancreatic insufficiency and those who were homozygous for the deltaF508 mutation.. Neonatal screening provides the opportunity to prevent malnutrition in infants with cystic fibrosis.

Topics: Body Height; Body Weight; Cystic Fibrosis; Humans; Infant; Infant, Newborn; Neonatal Screening; Nutrition Disorders; Nutritional Status; Prospective Studies; Trypsinogen

Detection of elevated levels of immunoreactive trypsinogen (IRT) in dried neonatal blood spots has been used as a screening test for cystic fibrosis. In other cystic fibrosis newborn-screening studies, a sweat chloride test is generally performed only if an infant has a persistent IRT level above a selected cutoff value on both the initial and subsequent specimens. Neither the timing of the second specimen nor the value of the cutoff point for the second specimen has been comprehensively evaluated. In this randomized, controlled study, 145,024 infants were screened in the neonatal period for cystic fibrosis using the 99.8 percentile (180 ng/mL) as the neonatal cutoff point. A total of 129 infants had elevated neonatal IRT levels and had negative results on sweat tests (false-positive by IRT screening). A total of 54 children with cystic fibrosis were identified in the screened and comparison groups. Excluding patients with meconium ileus, 4 infants with cystic fibrosis had neonatal IRT values less than 180 ng/mL, and an additional 9 infants with cystic fibrosis had values decline to less than 180 ng/mL within the first 2 1/2 months of age. The IRT values of infants with and without cystic fibrosis overlapped considerably beyond 30 days of age. These findings suggest that further refinement of cystic fibrosis screening methodology will be necessary to achieve an acceptable sensitivity and specificity.

Topics: Aging; Antibodies; Cystic Fibrosis; Humans; Incidence; Infant; Infant, Newborn; Infant, Premature; Intestinal Obstruction; Mass Screening; Meconium Aspiration Syndrome; Radioimmunoassay; Randomized Controlled Trials as Topic; Trypsinogen; Wisconsin

Cystic fibrosis (CF) is the most common autosomal recessive disorder in the Caucasian population, with an incidence of 1:5000 live births. In 2011, the screening of CF was implemented in the Andalusian Public Health newborn screening program by using immunoreactive trypsinogen and chloride sweat test (IRT/IRT/sweat test) determinations. Since then, 79 children have been diagnosed with CF in our health area (Western Andalusia). The aim of this study was to evaluate the efficiency of this screening method and to examinate the characteristics of those CF infants who had a negative screening but who were later diagnosed. In the 2011-2021 period 462,049 newborns were screened for CF using a two-step IRT determination and chloride sweat test. Sixty-three infants were diagnosed with CF in our health area thanks to the screening, and 15 CF children had a negative screening result and were finally diagnosed by molecular sequencing of the CFTR gene. The most frequent symptoms that led to the diagnosis of those false negative (FN) patients were hyponatremic dehydration (mean age 9.75 ± 1.5 months) and recurrent wheezing (mean age 24 ± 14.5 months). The molecular analysis of the CFTR gene on those FN showed a diversity of genotypes, identifying more than 10 different mutations. CONCLUSION: The rate of FN patients obtained in this study is inadmissibly high, and the protocol used in this region has not been updated despite the advances in genetic testing in the past 10 years. An improvement on CF newborn screening should be implemented, adding molecular analysis of the CFTR gene.

Topics: Child; Child, Preschool; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Testing; Humans; Infant; Infant, Newborn; Mutation; Neonatal Screening; Trypsinogen

Newborn screening (NBS) for cystic fibrosis (CF) was introduced in Switzerland in 2011 based on an immunoreactive trypsinogen (IRT)-DNA-IRT protocol. CF diagnosis was confirmed by sweat test and/or genetics but remained inconclusive for some newborns (cystic fibrosis transmembrane conductance regulator related metabolic syndrome (CRMS)/CF screen positive, inconclusive diagnosis (CFSPID)). We aimed to (1) Describe IRT levels in healthy newborns in the first year of life and by gestational age (GA), and (2) Compare IRT at two time points between healthy newborns and newborns with CF and CRMS/CFSPID.. Retrospective study.. National NBS database.. All children with an IRT measurement by heel prick test from 2011 to 2019.. None.. IRT values were extracted from the National NBS Laboratory, and clinical characteristics of positively screened children from the CF-NBS database. Second IRT assessment in positively screened children was usually performed after 18-24 days. We calculated internal IRT Z-Scores and multiples of the median to compare our results across different laboratory tools.. Among 815 899 children; 232 were diagnosed with CF, of whom 36 had meconium ileus (MI); 27 had CRMS/CFSPID. Among all samples analysed, mean IRT Z-Scores were higher for newborns with GA <33 weeks and ≥43 weeks (all Z-Scores >0.11) compared with term babies (all Z-Scores ≤0.06). Repeated IRT Z-Scores after a median (IQR) of 19 (17-22) days remained high for infants with CF with or without MI but decreased for infants with CRMS/CFSPID.. Measurement of a second IRT value can help distinguish between children with CRMS/CFSPID and CF, early in life.

Topics: Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Metabolic Syndrome; Neonatal Screening; Retrospective Studies; Trypsinogen

The aim of this study was to record the current status of newborn bloodspot screening (NBS) for CF across Europe and assess performance.. Survey of representatives of NBS for CF programmes across Europe. Performance was assessed through a framework developed in a previous exercise.. In 2022, we identified 22 national and 34 regional programmes in Europe. Barriers to establishing NBS included cost and political inertia. Performance was assessed from 2019 data reported by 21 national and 21 regional programmes. All programmes employed different protocols, with IRT-DNA the most common strategy. Six national and 11 regional programmes did not use DNA analysis.. Integrating DNA analysis into the NBS protocol improves PPV, but at the expense of increased carrier and CFSPID recognition. Some programmes employ strategies to mitigate these outcomes. Programmes should constantly strive to improve performance but large datasets are needed to assess outcomes reliably.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Trypsinogen

Phasing of heterozygous alleles is critical for interpretation of

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant, Newborn; Intestinal Obstruction; Meconium; Meconium Ileus; Trypsin; Trypsinogen

Newborn screening for cystic fibrosis (CF) has been underway universally in the United States for more than a decade, as well in most European countries, and algorithms have been evolving throughout this period with quality improvement projects as immunoreactive trypsinogen (IRT) determinations alone have been transformed to a 2-tier strategy with DNA analyses.. To apply next generation sequencing (NGS) as a screening method to expand the DNA tier and identify substantially more variants in the CF transmembrane conductance regulator (CFTR) gene to enhance sensitivity and equity while minimizing incidental findings.. Sequential evaluation and improvement plan in three phases using algorithm modifications coupled to statewide follow up and analysis of screening outcomes.. After demonstrating feasibility in the first phase, we studied an IRT/NGS algorithm that included CFTR Variants with Varying Clinical Consequences (VVCCs). This revealed a high identification of CF patients with 2-variants detected through screening, but for every CF case there were 1.4 with CF metabolic syndrome/CF screen positive, inconclusive diagnosis (CRMS/CFSPID). This led us to a third phase of improvement in which the VVCCs were eliminated except for R117H, resulting in 94% 2-variant detection of patients and 0.44:1 ratio of CRMS/CFSPID to CF.. NGS can be used with IRT as an effective method of identifying infants at risk for CF without an appreciable increase in detection of carriers. Its potential added value includes facilitating equity, enhancing sensitivity and detecting more CF patients with 2-variants during the screening process.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Heterozygote; High-Throughput Nucleotide Sequencing; Humans; Infant; Infant, Newborn; Mutation; Neonatal Screening; Trypsinogen

Cystic fibrosis (CF) newborn screening (NBS) algorithms in the United States vary by state. Differences in CF NBS algorithms could potentially affect the detection rate of CF newborns and lead to disparities in CF diagnosis amongst different racial and ethnic groups.. Generate a database of CF NBS algorithms in the United States and identify processes that may potentially lead to missed diagnoses or lead to healthcare disparities.. We sent an online survey to state and regional CF and NBS leaders about the type and threshold of immunoreactive trypsinogen (IRT) cutoff used and methods used for CFTR  gene variant analysis. Follow-up by email and phone was done to ensure a response from every state, clarify responses, and resolve discordances.. There is wide variation in the NBS algorithms employed by different states. Approximately half the states use a floating IRT cutoff, and half use a fixed IRT cutoff. CFTR variant analysis also varies widely, with two states analyzing only for the F508del variant and four states incorporating CFTR gene sequencing. The other states use CFTR variant panels ranging from 23 to 365 CFTR variants.. CF NBS algorithms vary widely amongst the different states in the United States, which affects the ability of CF NBS to diagnose newborn infants with CF consistently and uniformly across the country and potentially may miss more infants with CF from minority populations. Our results identify an important area for quality improvement in CF NBS.

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Testing; Humans; Infant, Newborn; Mutation; Neonatal Screening; Trypsinogen; United States

We aimed to evaluate cutoff values of immunoreactive trypsinogen (IRT)/IRT and determine relationship between IRT values and clinical characteristics of children with cystic fibrosis (CF). This study is cross-sectional study. Data of children with positive newborn screening (NBS) between 2015 and 2021 were evaluated in three pediatric pulmonology centers. Age at admission, sex, gestational age, presence of history of meconium ileus, parental consanguinity, sibling with CF, and doll-like face appearance, first and second IRT values, sweat chloride test, fecal elastase, fecal fat, biochemistry results, and age at CF diagnosis were recorded. Sensitivity and specificity of IRT cutoff values were evaluated. Of 815 children with positive NBS, 58 (7.1%) children were diagnosed with CF. Median values of first and second IRT were 157.2 (103.7-247.6) and 113.0 (84.0-201.5) μg/L. IRT values used in current protocol, sensitivity was determined as 96.6%, specificity as 17.2% for first IRT, and 96.6% sensitivity, 20.5% specificity for second IRT. Positive predictive value (PPV) was determined as 7.1%. When cutoff value for first IRT was estimated as 116.7 μg/L, sensitivity was 69.0% and specificity was 69.6%, and when cutoff value was set to 88.7 μg/L for second IRT, sensitivity was 69.0% and specificity was 69.0%. Area under curve was 0.757 for first and 0.763 for second IRT (p < 0.001, p < 0.001, respectively). PPV was calculated as 4.3%.    Conclusion: Although sensitivity of CF NBS is high in our country, its PPV is significantly lower than expected from CF NBS programs. False-positive NBS results could have been overcome by revising NBS strategy. What is Known: • Although immunoreactive trypsinogen elevation is a sensitive test used in cystic fibrosis newborn screening, its specificity is low. • In countries although different algorithms are used, all strategies begin with the measurement of immunoreactive trypsinogen in dried blood spots. What is New: • In our study, it was shown that use of the IRT/IRT protocol for cystic fibrosis newborn screening is not sufficient for the cut-off values determined by the high number of patients. • Newborn screening strategy should be reviewed to reduce false positive newborn screening results.

Topics: Child; Cross-Sectional Studies; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant, Newborn; Neonatal Screening; Sensitivity and Specificity; Trypsinogen

Universal implementation of cystic fibrosis (CF) newborn screening (NBS) has led to the diagnostic dilemma of infants with CF screen-positive, inconclusive diagnosis (CFSPID), with limited guidance regarding prognosis and standardized care. Rates of reclassification from CFSPID to CF vary and risk factors for reclassification are not well established. We investigated whether clinical characteristics are associated with the risk of reclassification from CFSPID to a CF diagnosis.. Children with a positive CF NBS were recruited from two sites in California. Retrospective, longitudinal, and cross-sectional data were collected. A subset of subjects had nasal epithelial cells collected for CF transmembrane conductance regulator (CFTR) functional assessment. Multivariate logistic regression was used to assess the risk of reclassification.. A total of 112 children completed the study (CF = 53, CFSPID = 59). Phenotypic characteristics between groups showed differences in pancreatic insufficiency prevalence, immunoreactive trypsinogen (IRT) levels, and Pseudomonas aeruginosa (PSA) colonization. Spirometry measures were not different between groups. Nasal epithelial cells from 10 subjects showed 7%-30% of wild-type (WT)-CFTR (wtCFTR) function in those who reclassified and 27%-67% of wtCFTR function in those who retained the CFSPID designation. Modeling revealed that increasing sweat chloride concentration (sw[Cl. Increasing sw[Cl

Topics: Child; Chlorides; Cross-Sectional Studies; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Neonatal Screening; Retrospective Studies; Sweat; Trypsinogen

To assess the accuracy of sweat conductivity among newborns and very young infants.. Prospective, population-based, diagnostic test accuracy study.. Public Statewide Newborn Screening Programme where the incidence rate of cystic fibrosis (CF) is ≈1:11 000.. Newborns and very young infants with positive two-tiered immunoreactive trypsinogen.. Sweat conductivity and sweat chloride were performed simultaneously, on the same day and facility by independent technicians, with the cut-off values of 80 mmol/L and 60 mmol/L, respectively.. Sensitivity, specificity, positive and negative predictive values (PPV and NPV), overall accuracy, positive and negative likelihood ratios (+LR, -LR) and post (sweat conductivity (SC)) test probability were calculated to assess SC performance.. 1193 participants were included, 68 with and 1108 without CF, and 17 with intermediate values. The mean (SD) age was 48 (19.2) days, ranging from 15 to 90 days. SC yielded sensitivity of 98.5% (95% CI 95.7 to 100), specificity of 99.9% (95% CI 99.7 to 100), PPV of 98.5% (95% CI 95.7 to 100) and NPV of 99.9% (95% CI 99.7 to 100), overall accuracy of 99.8% (95% CI 99.6 to 100), +LR of 1091.7 (95% CI 153.8 to 7744.9) and -LR of 0.01 (95% CI 0.00 to 0.10). After a positive and negative sweat conductivity result, the patient's probability of CF increases around 350 times and drops to virtually zero, respectively.. Sweat conductivity had excellent accuracy in ruling in or ruling out CF after positive two-tiered immunoreactive trypsinogen among newborns and very young infants.

Topics: Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Diagnostic Tests, Routine; Humans; Infant; Infant, Newborn; Neonatal Screening; Prospective Studies; Sweat; Trypsinogen

Airway inflammation starts in early life in cystic fibrosis (CF) and limited, objective markers are available to help identify infants with increased inflammation. We aimed to investigate neutrophil, lymphocyte ratio (NLR), mean platelet volume (MPV) and immunoreactive trypsinogen (IRT) to be a possible inflammatory biomarker for CF in infancy.. This was a retrospective cohort study in three centers. Between January 2015 and December 2022, children with CF newborn screening (NBS) positivity and diagnosed as CF were included in the study. Correlation analysis were performed with NLR, MPV, IRT and follow-up parameters such as z-scores, modified Shwachman-Kulczycki score (mSKS) at the first, second, third and sixth ages and pulmonary function test (PFT) at the sixth age.. A total of 92 children with CF included in the study and 47.8% of them were female. There were no correlations between NLR, MPV and weight and height z-scores for all ages (p > 0.05), a negative correlation was found between MPV and body mass indexes (BMI) z-score at the age of 6 (r = -0.443, p = 0.038). No correlation was found between NLR, MPV and PFT parameters and mSKS at all ages (p > 0.05). There was a negative correlation between first IRT and BMI z-score at 6 years of age (r = -0.381, p = 0.046) and negative correlations between second IRT and weight and BMI z-score at the age of 6 (r = -0.462, p = 0.010; r = -0.437, p = 0.016, respectively).. Higher MPV and IRT levels during NBS period are associated with worse nutritional outcome which may reflect chronic inflammation. Children with higher MPV and IRT should be followed up closely in terms of chronic inflammation and nutritional status.

Topics: Biomarkers; Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Humans; Infant; Infant, Newborn; Inflammation; Male; Mean Platelet Volume; Neonatal Screening; Neutrophils; Retrospective Studies; Trypsinogen

Previous studies suggest that PAP-based CF protocols are suitable for newborn screening (NBS) for cystic fibrosis (CF) when newborns designated as CFSPID should not be detected. However, there are still discussions about the performance of IRT/PAP algorithms. We present the final results of a pilot study evaluating a IRT/PAP protocol with an IRT-dependent safety net (SN) conducted from 2008 to 2016 in southwestern Germany on nearly 500,000 newborns.. To achieve reliable data, all newborns were screened using both the PAP-based and a DNA-based CFNBS algorithm. PAP quantification and genetic analysis of the four most common CFTR mutations in Germany were performed in all newborns with IRT≥99.0 percentile. NBS was rated positive if either PAP was ≥1.6 µg/l and/or at least one CFTR mutation was detected. In addition, an IRT-dependent SN resulted in positive rating for both protocols if IRT was ≥99.9 percentile. To evaluate the IRT/PAP protocol, its performance was compared to that of the IRT/DNA protocol.. The IRT/PAP protocol with IRT-based SN used in the study achieved a sensitivity of 94%, if false-negative detected neonates with meconium ileus and those designated as CFSPID were excluded from analysis. CF/CFSPID ratio was 92. However, PPV of the IRT/PAP+SN protocol was with 10.3% very low.. PAP-based CFNBS protocols can be used, if less detection of CFSPID is desired. The IRT/PAP protocol with IRT-dependent SN evaluated here achieved adequate sensitivity but should probably be used in combination with a third-tier test to also achieve an acceptable PPV.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Germany; Humans; Infant, Newborn; Neonatal Screening; Pancreatitis-Associated Proteins; Pilot Projects; Sensitivity and Specificity; Trypsinogen

Newborn screening (NBS) for cystic fibrosis (CF) was implemented in our country on January 1, 2015, based on immunoreactive trypsinogen tests (IRT/IRT). Here, we aimed to evaluate the diagnoses of patients and follow-up process within the first 5 years of NBS from a tertiary care center.. This retrospective cohort study was conducted on patients who were admitted to our pediatric pulmonology department for sweat test (ST) via NBS. Patients with CF with negative NBS results and those with CF with positive NBS and joined our follow-up were also investigated. Clinical outcome measures were compared between patients with CF with positive and negative NBS.. Six hundred sixty infants who were referred for ST via NBS were included. Across the entire study population (n = 683), 11.4% of patients had CF (14.1% of had negative NBS in this CF group). The sensitivity of NBS was found as 84.9% and the positive predictive value (PPV) was 9.4%. The median age at diagnosis was older (p < 0.001), reluctance for feeding and Pseudobartter syndrome (PBS) were significantly higher at presentation in the negative NBS group. There was no statistically significant difference between the groups regarding weight-for-age (p = 0.899) and height-for-age (p = 0.491) in the first 2 years' follow-ups.. Our findings showed the low sensitivity and PPV of NBS; therefore, further studies based on all patients in our country are necessary for new cut-off values. PBS and reluctance for feeding should be alarm symptoms for CF even if the infants had negative NBS. Additionally, later diagnosis of patients who had negative NBS did not affect the nutritional outcomes; we need large-scale prospective studies to optimize nutritional benefits for all infants diagnosed via NBS.

Topics: Child, Preschool; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Neonatal Screening; Prospective Studies; Retrospective Studies; Tertiary Care Centers; Trypsinogen

Cystic fibrosis (CF) is a lethal recessive genetic disease caused by loss of function associated with mutations in the CF trans-membrane conductance regulator. It is highly prevalent (approximately 1 in 3,500) in Caucasians. The aim of this study was to compare demographic and clinical features, diagnostic tests, treatments, and complications of patients with CF whose newborn screening (NBS) with twice-repeated immune reactive trypsinogen testing was positive, normal, and not performed.. In this study, 359 of all 1,488 CF patients recorded in the CF Registry of Turkey in 2018, who had been born through the process of NBS, were evaluated. Demographic and clinical features were compared in patients diagnosed with positive NBS (Group 1), normal (Group 2), or without NBS (Group 3).. In Group 1, there were 299 patients, in Group 2, there were 40 patients, and in Group 3, there were 20 patients. Among all patients, the median age at diagnosis was 0.17 years. The median age at diagnosis was higher in Groups 2 and 3 than in Group 1 (P = 0.001). Fecal elastase results were higher in Group 2 (P = 0.033). The weight z-score was lower and chronic Staphylococcus aureus infection was more common in Group 3 (P = 0.017, P = 0.004, respectively).. Frequency of growth retardation and chronic S. aureus infection can be reduced with an early diagnosis using NBS. In the presence of clinical suspicion in patients with normal NBS, further analyses such as genetic testing should be performed, especially to prevent missing patients with severe mutations.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant, Newborn; Neonatal Screening; Staphylococcus aureus; Trypsinogen

Cystic fibrosis (CF) screen-positive infants with an inconclusive diagnosis (CFSPID) are infants in whom sweat testing and genetic analysis does not resolve a CF diagnosis. Lack of knowledge about the health outcome of these children who require clinical follow-up challenges effective consultation. Early predictive biomarkers to delineate the CF risk would allow a more targeted approach to these children.. Prospective, longitudinal, multicenter, Canada-wide cohort study of CF positive-screened newborns with 1 to 2 cystic fibrosis transmembrane conductance regulator gene variants, of which at least 1 is not known to be CF-causing and/or a sweat chloride between 30 and 59 mmol/L. These were monitored for conversion to a CF diagnosis, pulmonary, and nutritional outcomes.. The mean observation period was 7.7 (95% confidence interval 7.1 to 8.4) years. A CF diagnosis was established for 24 of the 115 children with CFSPID (21%) either because of reinterpretation of the cystic fibrosis transmembrane conductance regulator genotype or because of increase in sweat chloride concentration ≥60 mmol/L. An initial sweat chloride of ≥40 mmol/l predicted conversion to CF on the basis of sweat testing. The 91 remaining children with CFSPID were pancreatic sufficient and showed normal growth until school age. Pulmonary function as well as lung clearance index in a subgroup of children with CFSPID were similar to that of healthy controls.. Children with CFSPID have good nutritional and pulmonary outcomes at school age, but rates of reclassifying the diagnosis are high. The initial sweat chloride test can be used as a biomarker to predict the risk for CF in CFSPID.

Topics: Age Factors; Biomarkers; Canada; Child; Chlorides; Cohort Studies; Confidence Intervals; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Genetic Variation; Genotype; Humans; Infant, Newborn; Longitudinal Studies; Male; Neonatal Screening; Nutritional Status; Pancreatic Function Tests; Prospective Studies; Reference Values; Respiratory Function Tests; Sweat; Trypsinogen

Wales has an immunoreactive trypsin (IRT)-DNA cystic fibrosis (CF) newborn screening (NBS) programme. Most CF NBS false negative cases are due to an IRT concentration below the screening threshold. The accuracy of IRT results is dependent on the quality of the dried bloodspot (DBS) sample. The aim of this study was to determine the cause of false negative cases in CF NBS and their relationship to DBS quality.. Longitudinal birth cohort.. Wales 1996-2016.. Children with CF.. Identification of all CF patients with triangulation of multiple data sources to detect false negative cases.. False negative cases.. Over 20 years, 673 952 infants were screened and 239 were diagnosed with CF (incidence 1:2819). The sensitivity of the programme was 0.958, and positive predictive value was 0.476. Eighteen potential false negatives were identified, of whom eight were excluded: four screened outside Wales, two had complex comorbidities, no identified cystic fibrosis transmembrane conductance regulator (CFTR) variants on extended analysis and thus not considered to have CF and two were diagnosed after their 16th birthday. Of the 10 false negatives, 9 had a low DBS IRT and at least one common CFTR variant and thus should have received a sweat test under the programme. DBS cards were available for inspection for five of the nine false negative cases-all were classified as small/insufficient or poor quality.. The majority of false negatives had a low bloodspot IRT, and this was associated with poor quality DBS. The optimal means to improve the sensitivity of our CF NBS programme would be to improve DBS sample quality.

Topics: Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Dried Blood Spot Testing; False Negative Reactions; Humans; Incidence; Infant; Infant, Newborn; Meconium Ileus; Neonatal Screening; Predictive Value of Tests; Retrospective Studies; Selection Bias; Sweat; Trypsinogen; Wales

The benefits of early cystic fibrosis (CF) detection using newborn screening (NBS) has led to widespread use in NBS programs. Since 2002, a two-stage immunoreactive trypsinogen (IRT/IRT) screening strategy has been used as a CFNBS method in all public maternity units in the City of Buenos Aires, Argentina. However, novel screening strategies may be more efficient. The aim of this study is to prospectively compare two CFNBS strategies: IRT/IRT and IRT/PAP (pancreatitis-associated protein).. A two-year prospective study was performed. IRT was measured in dried blood samples collected 48-72 h after birth. When an IRT value was abnormal, PAP was determined, and a second visit was scheduled to obtain another sample for IRT before 25 days of life. Newborns with a positive CFNBS were referred for a confirmatory sweat test.. There were 69,827 births in the City of Buenos Aires during the period studied; 918 (1.31%) had an abnormal IRT. A total of 207 children (22.5%) failed to return for the second IRT, but only two PAP (0.2%) were not performed. IRT/IRT was more likely to lead to a referral for sweat testing than IRT/PAP (odds ratio 2.3 [95% confidence interval 1.8-2.9], p < .001). Sensitivity and specificity were: 80% and 100% and 86.5% and 82.6% for IRT/IRT and IRT/PAP strategies, respectively.. The IRT/PAP strategy is more sensitive than IRT/IRT and has similar specificity; it avoids a second visit and unnecessary sweat testing, and it reduces loss to follow-up in our population.

Topics: Antigens, Neoplasm; Argentina; Biomarkers, Tumor; Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Humans; Infant, Newborn; Lectins, C-Type; Neonatal Screening; Pancreatitis-Associated Proteins; Pregnancy; Prospective Studies; Sensitivity and Specificity; Trypsinogen

In Denmark, newborn screening (NBS) for cystic fibrosis (CF) was introduced on 1 May 2016. The implementation and results from the first 2 years of the national newborn CF screening program are presented.. The screening included immunoreactive trypsinogen (IRT), followed by evaluation for the F508del mutation when a value at or above the 50 ng/mL cutoff was present. In cases with a single F508del mutation or a very high IRT value above 145 ng/mL, next-generation sequencing of the CF transmembrane conductance regulator gene (CFTR) was performed.. Of 126 522 newborn infants 126 338 were tested (99.85%), and 4730 samples (3.7%) were assessed for CFTR mutations. Twenty-six infants were screen-positive and referred for diagnostic follow-up of whom 22 were confirmed to have a CF diagnosis, four had one known and one CFTR allele with unknown pathogenicity, classified as cystic fibrosis screening positive inconclusive diagnosis (CFSPID), PPV 84.6%. One of the four children classified as CFSPID was later found to carry the two identified CFTR variants in cis and was reclassified as a carrier of CF. We found two false negatives; one exhibited an IRT level above the 50 ng/mL cutoff but was below the 145 ng/mL very high cutoff and with no F508del mutation present. The second false-negative fell below the 50 ng/mL IRT cutoff but was diagnosed shortly after birth on the basis of meconium ileus. Screening sensitivity, 91.7%. Two hundred thirty-two children were identified as carriers of CF, which is twofold above the estimated annual number of carriers. All but one carrier were heterozygous for the F508del CFTR mutation. Sixteen percent of the sequenced samples revealed rare CFTR variants, which were classified as nonpathogenic in relation to CF.. During the first 2 years of NBS CF screening in Denmark, we identified close to the expected number of infants with CF using an algorithm based on IRT, presence of F508del mutation and comprehensive genetic analysis. CFSPID accounted for only a small minority, despite comprehensive CFTR sequencing, whereas more carriers than initially expected were identified.

Topics: Algorithms; Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Denmark; Female; Genetic Testing; Humans; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; Trypsinogen

Cystic fibrosis (CF) is a multisystem disorder that reduces quality of life and survival in affected individuals. In newborns, the release of pancreatic enzymes into the blood raises the levels of immunoreactive trypsinogen (IRT), the main marker for CF screening, which is detected in dried blood samples on filter paper by immunoenzymatic assays. In Cuba, CF has an estimated incidence of 1/9862 live births and should be included in the national basic newborn screening (NBS) panel given its benefits in terms of nutrition, lung function and survival. The Immunoassay Center develops and produces diagnostic kits allowing the establishment of large-scale NBS programs for inherited metabolic disorders in Cuba and other Latin American countries. IRT-specific monoclonal antibodies (MAbs) obtained at the Immunoassay Center are essential for developing an affordable immunoassay for IRT to support CF NBS in our low-income country. An immunization scheme with trypsinogen-1 originated two IgG1-producing murine hybridomas. 4C9C9 and 4C9E11 MAbs recognized different determinants on both trypsin-1 and trypsin-2 molecules. Both antibodies identified conformational epitopes on the molecule of trypsin-1 and of its zymogen. As 4C9E11 MAb cross-reacted with proteins structurally and functionally related to trypsinogen, it was used as revealing antibody in a sandwich-type UMELISA® assay for IRT determination with 4C9C9 MAb for capture. This combination, aside from detecting several commercially available trypsins, adequately quantified IRT from dried blood samples on filter paper of newborns. The evaluation of the assay's accuracy yielded percentage recoveries ranging 93.3-109.2% for commercial controls. The properties of the studied MAbs demonstrate their suitability for being used in a sandwich-type UMELISA® assay for the CF NBS in Cuba.

Topics: Animals; Antibodies, Monoclonal, Murine-Derived; Biomarkers; Cystic Fibrosis; Female; Humans; Hybridomas; Immunoassay; Infant, Newborn; Mice; Mice, Inbred BALB C; Neonatal Screening; Trypsin; Trypsinogen

To characterize the phenotypic expression of children with conductance regulator-related metabolic syndrome (CRMS)/cystic fibrosis screen positive inconclusive diagnosis (CFSPID) designation after positive newborn screening, reassign labeling if applicable and better define these children's prognosis.. A multicenter cohort with CRMS/CFSPID designation was matched with cystic fibrosis (CF)-diagnosed cohort. Cohorts were prospectively compared on baseline characteristics, cumulative data and when they reached 6 to 7 years at endpoint assessment.. Compared to infants with CF (n = 63), the CRMS/CFSPID cohort (n = 63) had initially lower immunoreactive trypsinogen (IRT) and sweat chloride (SC) values, delayed visits, less symptoms, and better nutritional status; during follow-up, they had fewer hospitalizations, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus identification, CF comorbidities, and treatment burden. At endpoint assessment, they presented a milder pulmonary phenotype on Brody computed tomography scores (0.0[0.0; 2.0] vs 13[2.0; 31.0]; P < .0001, respectively), Wisconsin and Brasfield chest radiograph scores, pulmonary function tests, and improved nutritional status. Among the inconclusive CF diagnosis cohort, 28 cases (44%) converted to CF diagnosis based on genotype (44%), SC (28%) or both (28%); yet, comparing those with or without final CF diagnosis, we found no differences, possibly related to their young age and mild degree of lung disease. In the total cohort, we found significant associations between Brody scores and IRT, SC values, genotype, Wisconsin and Brasfield score and spirometry.. The matched CRMS/CFSPID and CF cohorts showed differences in outcomes. By a mean age of 7.6 years, a high proportion of the CRMS/CFSPID cohort converted to CF. Our results highlight that monitoring at CF clinics until at least 6 years is needed as well as further studies.

Topics: Child; Chlorides; Cohort Studies; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Genotype; Hospitalization; Humans; Infant, Newborn; Male; Metabolic Diseases; Methicillin-Resistant Staphylococcus aureus; Neonatal Screening; Phenotype; Prognosis; Pseudomonas aeruginosa; Sweat; Trypsinogen

Background In Cuba, no screening program for cystic fibrosis (CF) has been implemented yet. The ultramicro enzyme-linked immunosorbent assay (UMELISA)® TIR NEONATAL has been developed for the measurement of immunoreactive trypsin (IRT) in dried blood spots on filter paper. The analytical performance of the kit was evaluated in the national network of laboratories. Methods Newborn dried blood samples (DBS) were evaluated in 16 laboratories. An IRT/IRT/DNA protocol was followed using a cut-off value of 50 ng/mL. The mean, median and percentiles of the distribution were calculated and a two-sample t-test with unequal variance was used for statistical analysis. Influence of perinatal factors on IRT levels was analyzed. Results From January to June 2018, 6470 newborns were studied, obtaining a mean IRT value of 12.09 ng/mL (ranging 0-358 ng/mL) and a median of 8.99 ng/mL. Fifty-two samples (0.78%) were above the cut-off level and 16 samples (0.24%) were elevated in the re-screening process. One of them was confirmed positive by molecular biology (phe508del/c.3120 + 1G > A), constituting the first newborn screened and diagnosed early in Cuba. Second DBS samples were collected on average at 14 days and processed in the laboratory at 16 days of birth. Significant differences were observed (p < 0.05) when evaluating the influence of gender, birth weight (BW) and gestational age (GA) on the IRT values. Lower IRT concentrations were found in samples processed after 10 days of collection. Conclusions The performance of UMELISA® TIR NEONATAL in the laboratories has been satisfactory; hence CF newborn screening (NBS) was extended throughout the country from January 2019.

Topics: Algorithms; Cuba; Cystic Fibrosis; Dried Blood Spot Testing; Enzyme-Linked Immunosorbent Assay; Female; Humans; Infant, Newborn; Male; Mutation; Neonatal Screening; Pilot Projects; Sensitivity and Specificity; Trypsinogen

The Hospital of the Ribeirão Preto Medical School, University of São Paulo is one of the three screening centers in São Paulo State, Brazil, and has included a test for cystic fibrosis (CF) since February 6, 2010, by a court order. We evaluated the first five years of this CF-newborn screening program. The original immunoreactive trypsinogen (IRT)/IRT screening protocol was adopted in Brazil. A total of 173,571 newborns were screened, 1,922 (1.1%) of whom showed IRT1 ≥ 70ng/mL. Of these, 1,795 (93.4%) collected IRT2, with elevated results (IRT2 ≥ 70ng/mL) in 102 of them (5.2%). We identified a total of 26 CF cases during this period, including three CF cases that were not detected by the CF-newborn screening. The incidence of the disease among the screened babies was 1:6,675 newborns screened. Median age at the initial evaluation was 42 days, comparable to that of neonates screened with the IRT/DNA protocol. Almost all infants with CF already exhibited some manifestations of the disease during the neonatal period. The mutation most frequently detected in the CF cases was F508del. These findings suggest the early age at the beginning of treatment at our center was due to the effort of the persons involved in the program regarding an effective active search. Considering the false negative results of CF-newborn screening and the early onset of clinical manifestations of the disease in this study, pediatricians should be aware of the diagnosis of CF even in children with negative test.

Topics: Brazil; Child; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Neonatal Screening; Trypsinogen

The objective of this study was to determine if infants carrying 1 cystic fibrosis transmembrane receptor (CFTR) mutation demonstrate pancreatic inflammation in response to tobacco exposure.. Cystic fibrosis carrier infants aged 4 to 16 weeks were prospectively enrolled. Tobacco exposure was assessed by survey and maternal hair nicotine analysis. Serum immunoreactive trypsinogen (IRT) levels at birth and at the time of recruitment were analyzed relative to the presence or absence of tobacco exposure. The effect of the severity of the CFTR mutation carried by the infant on the tobacco-IRT relationship was also analyzed.. Forty-eight infants completed the study. Newborn screen and follow-up IRT levels were not different between exposed infants (19 by hair analysis) and nonexposed infants (29 by hair analysis). Follow-up IRT levels were lower in infants with more severe CFTR mutations (P = 0.005). There was no difference in follow-up IRT based on CFTR mutation severity in exposed infants. Nonexposed infants with milder CFTR mutations had higher median IRT values on follow-up testing than those with more severe CFTR mutations (P < 0.05).. The pancreas of cystic fibrosis carrier infants is affected by tobacco exposure, and those carrying less severe CFTR mutations may be more susceptible to tobacco effects.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Genetic Testing; Hair; Heterozygote; Humans; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; Nicotine; Pancreatitis; Pilot Projects; Pregnancy; Prenatal Exposure Delayed Effects; Prospective Studies; Smoking; Tobacco Smoke Pollution; Trypsinogen

Newborn screening (NBS) for cystic fibrosis (CF) not only identifies infants with a diagnosis of CF, but also those with an uncertain diagnosis of cystic fibrosis (CF), i.e. CF transmembrane conductance regulator (CFTR)-related metabolic syndrome (CRMS) or CF screen positive inconclusive diagnosis (CFSPID). These infants have an uncertain long-term outcome and it is currently unclear around time of diagnosis, which infants are at higher risk of later fulfilling a CF diagnosis. In this study, we hypothesised that immunoreactive trypsinogen (IRT) levels, used in NBS as a marker of pancreatic disease and function, may reflect the degree of CFTR dysfunction in each individual and therefore would help to identify those with CRMS/CSPID who are later at risk for meeting the criteria of CF.. In this longitudinal, prospective study, infants with CRMS/CFSPID and CF were recruited and followed in 9 CF clinics (Canada and Italy). We compared NBS IRT levels between CF and CRMS/CFSPID, and between children with CRMS/CFSPID→CF and CRMS/CFSPID→CRMS/CFSPID during the period of June 2007 to April 2016.. Ninety eight CRMS/CFSPID and 120 CF subjects were enrolled. During the study period, 14 (14.3%) CRMS/CFSPID subjects fulfilled the diagnostic criteria for CF (CRMS/CFSPID→CF), while the diagnosis remained uncertain (CRMS/CFSPID→ CRMS/CFSPID) in 84 (85.7%) subjects. Significantly higher NBS IRT concentrations (ng/ml) were present in CF than CRMS/CFPSID (median (interquartile range): 143.8 (99.8-206.2) vs. 75.0 (61.0-105.9); P < 0.0001). Infants with CRMS/CFSPID→CF (n = 14) had significantly higher NBS IRT concentrations (ng/ml) than CRMS/CFSPID→ CRMS/CFSPID (n = 83) (median (interquartile range): 108.9 (72.3-126.8) vs. 73.7(60.0-96.0); P = 0.02).. Amongst infants who tested positive on NBS for CF, there is a gradation of elevated NBS IRT concentrations. Infants with CF have higher NBS IRT levels than CRMS/CFPSID, and higher NBS IRT concentrations were present in infants with CRMS/CFSPID→CF than CRMS/CFSPID→ CRMS/CFSPID. NBS IRT concentrations, in concert with other factors, may have the potential to predict the likelihood of CF amongst infants with CRMS/CFSPID.

Topics: Cystic Fibrosis; Humans; Infant, Newborn; Longitudinal Studies; Neonatal Screening; Prospective Studies; Trypsinogen

Since January 2015, the Cystic Fibrosis Newborn Screening (CFNS) program has been implemented in Turkey. We aimed to evaluate the demographic, clinical, and laboratory data of cases referred from the CFNS program and to determine the most suitable cut-off value for immunoreactive trypsinogen (IRT)-1 and immunoreactive trypsinogen (IRT-2) that are used in the CFNS program in Turkey.. A total of 156 Turkish Caucasian subjects were determined as positive cases during 3 years, from January 2015 to January 2018, and were referred to the pediatric pulmonology clinics of Akdeniz University Hospital, Antalya, Turkey, for the national CFNS program. The evaluation was made considering the IRT-1 and IRT-2 values, demographic characteristics, sweat test results, CFTR genotypes, and diagnoses.. Nine patients were diagnosed with cystic fibrosis (CF). Eight were diagnosed with CF-related metabolic syndromes and three were determined to be CF carriers. The ratio of CF to CF-related metabolic syndrome was determined as 1.1:1. Considering the limits of the present CFNS program and the IRT method, the positive predictive value (PPV) for the referred cases was determined as 5.8%. When a cut-off value of 105.6 ng/mL was taken for IRT-1, sensitivity was 100%, specificity was 59%, and PPV was 12.8%. For a cut-off value of 88.75 ng/mL for IRT-2, sensitivity was determined as 90%, specificity as 65%, and PPV as 15.2%.. This is the first detailed clinical study to evaluate the data from the CFNS program along the Mediterranean coast of Turkey. As false positive results are extremely high in Turkey, there is an urgent need for revision of the IRT-1 and IRT-2 limits by evaluating the data of the whole country.

Topics: Calcium-Binding Proteins; Cystic Fibrosis; Humans; Infant; Infant, Newborn; Male; Microfilament Proteins; Neonatal Screening; ROC Curve; Sensitivity and Specificity; Trypsin; Trypsinogen; Turkey

Topics: Cystic Fibrosis; Diagnostic Tests, Routine; Genetic Testing; Humans; India; Infant, Newborn; Male; Mutation; Neonatal Screening; Trypsinogen

Objectives To evaluate the French cystic fibrosis newborn screening algorithm, based on data tracked by a centralized monitoring process, from 2002 to 2014. The programme aimed to attain European Standards in terms of positive predictive value, sensitivity, the ratio of screen positive patients diagnosed with cystic fibrosis to infants who screen positive but with inconclusive diagnosis (CFSPID), and time to diagnosis. Methods Retrospective analysis of programme performance, compliance with the algorithm, and changes in screening strategy. Results Modifications in the flow chart protocol improved the positive predictive value to 0.31 while maintaining the sensitivity at 0.95. Among infants diagnosed with cystic fibrosis, or identified as CFSPID, sweat test results were obtained for 94%, and two mutations were identified after exhaustive screening for the gene, when applicable, in 99.6%. The rate of pending diagnosis was very low (0.5%). The ratio of infants with cystic fibrosis:CFSPID was 6.3:1. Age at initial visit at the CF centre was ≤ 35 days, respectively, in 53%/26%. Conclusion Performances were in agreement with European standards, but timeliness of initial visit needed improvement. Our data complement an accumulating body of evidence demonstrating that attention must be paid to such ethical considerations as limiting carrier detection and inconclusive diagnosis. Newborn screening programmes should have a rigorous centralized monitoring process to warrant adjustments for improving performance to attain consensus guidelines.

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; France; Humans; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; Retrospective Studies; Sensitivity and Specificity; Sweat; Time Factors; Trypsinogen

To use the results of the first five years of a cystic fibrosis newborn screening program to estimate the cystic fibrosis birth prevalence and spectrum of cystic fibrosis transmembrane conductance regulator ( CFTR) gene variants in Yucatan, Mexico.. Screening was performed from 2010 to 2015, using two-tier immunoreactive trypsinogen testing, followed by a sweat test. When sweat test values were >30 mmol/L, the CFTR gene was analyzed.. Of 96,071 newborns screened, a second sample was requested in 119 cases. A sweat test was performed in 30 newborns, and 9 possible cases were detected (seven confirmed cystic fibrosis and two inconclusive). The most frequently detected CFTR pathogenic variant (5/14 cystic fibrosis alleles, 35.7%) was p.(Phe508del); novel p.(Ala559Pro) and p.(Thr1299Hisfs*29) pathogenic variants were found.. Cystic fibrosis birth prevalence in southeastern Mexico is 1:13,724 newborns. Immunoreactive trypsinogen blood concentration is influenced by gestational age and by the time of sampling. The spectrum of CFTR gene variants in Yucatan is heterogeneous.

Topics: Alleles; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Humans; Infant, Newborn; Male; Mexico; Mutation; Neonatal Screening; Prevalence; Reproducibility of Results; Sweat; Trypsinogen

This paper aims to describe the added value of combining cost-effectiveness and ethical evaluations when the preferences of the decision maker toward cost-effectiveness evaluation outcomes are not known, with the French national neonatal screening of cystic fibrosis (CF) as a case-study.. A cost-effectiveness analysis comparing four CF neonatal screening strategies, with or without DNA testing, was performed. Ethical positions toward their outcomes were described. In addition, a post-hoc analysis of the ethical issues being considered relevant from the decision-makers' perspective was conducted.. Two strategies were found equally cost-effective. Among them, choosing the non-DNA or a DNA-based strategy constrains the decision maker to render a judgement between different ethical issues or disagreements associated with the screening program.. The analysis supports the relevance of combining cost-effectiveness and ethics evaluation in developing health policy, as a way to reveal or clarify the motives associated with health. The choice of the decision maker to favor the DNA-based strategy, which was not originally recommended, creates the opportunity to make explicit the role played by ethical issues in the decision.

Topics: Cost-Benefit Analysis; Cystic Fibrosis; Decision Making; Diagnostic Errors; France; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Pancreatitis-Associated Proteins; Trypsinogen; Uncertainty

Cystic fibrosis (CF) is a severe autosomal recessive disorder. It is caused by mutations in the CF transmembrane conductance regulator gene. Early diagnosis of CF can be carried out by determining high immunoreactive trypsinogen (IRT) blood values in newborns. A simple sandwich-type ultramicroELISA assay (UMELISA®) has been developed for the measurement of IRT in dried blood spots on filter paper. Strips coated with a high affinity monoclonal antibody directed against IRT are used as solid phase, to ensure the specificity of the assay. The assay is carried out within 20 h. The useful rank of the curve is 0-500 ng/mL, and the lowest detectable concentration is 4.8 ng/mL. Intra- and inter-assay coefficients of variation were lower than 10%. The recovery mean value was 100.3 ± 11.2%. Cross-reactivity with proteins structurally related to IRT (α2-macroglobulin, α1-antitrypsin, and human chymotrypsin) was lower than the detection limit of the assay. Four thousand four hundred six newborn samples from the Cuban Newborn Screening Program were analyzed, and the mean IRT concentration was 12.8 ng/mL. Higher IRT values were obtained when samples were eluted overnight. Regression analysis showed a good correlation with the commercially available AutoDELFIA® Neonatal IRT kit (n = 3948, r = 0.885, ƙ = 0.976, p < 0.01). The analytical performance characteristics of our UMELISA® TIR Neonatal suggest that it can be used for the neonatal screening of CF.

Topics: Cross Reactions; Cystic Fibrosis; Dried Blood Spot Testing; Enzyme-Linked Immunosorbent Assay; Humans; Paper; Sensitivity and Specificity; Trypsinogen

Topics: Child; Child, Preschool; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Mutation; Sweat; Trypsinogen

Newborn screening for cystic fibrosis (CF), a chronic progressive disease affecting mucus viscosity, has been beneficial in both improving life expectancy and the quality of life for individuals with CF. In New York State from 2007 to 2012 screening for CF involved measuring immunoreactive trypsinogen (IRT) levels in dried blood spots from newborns using the IMMUCHEM(™) Blood Spot Trypsin-MW ELISA kit. Any specimen in the top 5% IRT level underwent DNA analysis using the InPlex(®) CF Molecular Test. Of the 1.48 million newborns screened during the 6-year time period, 7631 babies were referred for follow-up. CF was confirmed in 251 cases, and 94 cases were diagnosed with CF transmembrane conductance regulated-related metabolic syndrome or possible CF. Nine reports of false negatives were made to the program. Variation in daily average IRT was observed depending on the season (4-6 ng/ml) and kit lot (<3 ng/ml), supporting the use of a floating cutoff. The screening method had a sensitivity of 96.5%, specificity of 99.6%, positive predictive value of 4.5%, and negative predictive value of 99.5%.. Considerations for CF screening algorithms should include IRT variations resulting from age at specimen collection, sex, race/ethnicity, season, and manufacturer kit lots.. Measuring IRT level in dried blood spots is the first-tier screen for CF. Current algorithms for CF screening lead to substantial false-positive referral rates.. IRT values were affected by age of infant when specimen is collected, race/ethnicity and sex of infant, and changes in seasons and manufacturer kit lots The prevalence of CF in NYS is 1 in 4200 with the highest prevalence in White infants (1 in 2600) and the lowest in Black infants (1 in 15,400).

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Genetic Testing; Humans; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; New York; Prevalence; Sensitivity and Specificity; Trypsinogen

To compare the cost effectiveness of adding a pancreatitis-associated protein (PAP) assay to common immunoreactive trypsinogen (IRT) and DNA cystic fibrosis (CF) newborn screening strategies.. Using data collected on 553,167 newborns, PAP cut-offs were calculated based on non-inferiority of the detection rates of classical forms of CF. Cost effectiveness was considered from the third-party payer's perspective using only direct medical costs, and the unit costs of PAP assays were assessed based on a micro-costing study. Robustness of the cost-effectiveness estimates was assessed, taking the secondary outcomes of screening (ie. detecting mild forms and CF carriers) into account.. IRT/DNA, IRT/PAP, and IRT/PAP/DNA strategies had similar detection rates for classical forms of CF, but the strategies involving PAP assays detected smaller numbers of mild forms of CF. The IRT/PAP strategy was cost-effective in comparison with either IRT/DNA or IRT/PAP/DNA. IRT/PAP/DNA screening was cost-effective in comparison with IRT/DNA if relatively low value was assumed to be attached to the identification of CF carriers.. IRT/PAP strategies could be strictly cost-effective, but dropping DNA would mean the test could not detect CF carriers. IRT/PAP/DNA strategies could be a viable option as they are significantly less costly than IRT/DNA, but still allow CF carrier detection.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Cost-Benefit Analysis; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; France; Humans; Infant, Newborn; Lectins, C-Type; Male; Neonatal Screening; Pancreatitis-Associated Proteins; Prospective Studies; Sensitivity and Specificity; Trypsinogen

Norway introduced newborn screening for cystic fibrosis (CF) March 1, 2012. We present results from the first three years of the national newborn CF screening program.. Positive primary screening of immunoreactive trypsinogen (IRT) was followed by DNA testing of the Cystic fibrosis transmembrane conductance regulator (CFTR) gene. Infants with two CFTR mutations were reported for diagnostic follow-up.. Of 181,859 infants tested, 1454 samples (0.80%) were assessed for CFTR mutations. Forty children (1:4546) had two CFTR mutations, of which only 21 (1:8660) were confirmed to have a CF diagnosis. The CFTR mutations differed from previously clinically diagnosed CF patients, and p.R117H outnumbered p.F508del as the most frequent mutation. One child with a negative IRT screening test was later clinically diagnosed with CF.. The CF screening program identified fewer children with a conclusive CF diagnosis than expected. Our data suggest a revision of the IRT/DNA protocol.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Genetic Testing; Humans; Infant, Newborn; Male; Mutation; National Health Programs; Needs Assessment; Neonatal Screening; Norway; Program Evaluation; Symptom Assessment; Trypsinogen

The aim of newborn screening (NBS) for CF is to detect children with 'classic' CF where early treatment is possible and improves prognosis. Children with inconclusive CF diagnosis (CFSPID) should not be detected, as there is no evidence for improvement through early treatment. No algorithm in current NBS guidelines explains what to do when sweat test (ST) fails. This study compares the performance of three different algorithms for further diagnostic evaluations when first ST is unsuccessful, regarding the numbers of children detected with CF and CFSPID, and the time until a definite diagnosis.. In Switzerland, CF-NBS was introduced in January 2011 using an IRT-DNA-IRT algorithm followed by a ST. In children, in whom ST was not possible (no or insufficient sweat), 3 different protocols were applied between 2011 and 2014: in 2011, ST was repeated until it was successful (protocol A), in 2012 we proceeded directly to diagnostic DNA testing (protocol B), and 2013-2014, fecal elastase (FE) was measured in the stool, in order to determine a pancreas insufficiency needing immediate treatment (protocol C).. The ratio CF:CFSPID was 7:1 (27/4) with protocol A, 2:1 (22/10) with protocol B, and 14:1 (54/4) with protocol C. The mean time to definite diagnosis was significantly shorter with protocol C (33days) compared to protocol A or B (42 and 40days; p=0.014 compared to A, and p=0.036 compared to B).. The algorithm for the diagnostic part of the newborn screening used in the CF centers is important and affects the performance of a CF-NBS program with regard to the ratio CF:CFSPID and the time until definite diagnosis. Our results suggest to include FE after initial sweat test failure in the CF-NBS guidelines to keep the proportion of CFSPID low and the time until definite diagnosis short.

Topics: Algorithms; Clinical Protocols; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Early Diagnosis; Early Medical Intervention; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Pancreatic Elastase; Prognosis; Quality Improvement; Sweat; Switzerland; Time Factors; Trypsinogen

The detection of two frequent CFTR disease-causing variations in the context of a newborn screening program (NBS) usually leads to the diagnosis of cystic fibrosis (CF) and a relevant genetic counseling in the family. In the present study, CF-causing variants p.Phe508del (F508del) and c.3140-26A>G (3272-26A>G) were identified on a neonate with positive ImmunoReactive Trypsinogen test by the Elucigene™ CF30 kit. The CF diagnosis initially suggested, despite three inconclusive Sweat Chloride Tests (SCT), was finally ruled out after the familial segregation study combined with a negative SCT. Haplotype studies, based on the comparison of 80 p.Phe508del haplotypes, suggested a probable de novo occurrence of c.3140-26A>G on the p.Phe508del ancestral allele in this family. This false positive case emphasizes the importance of SCT in the NBS strategy. Moreover, it raises the need for familial segregation studies in CF and in overall molecular diagnosis strategy of autosomal recessive diseases.

Topics: Alleles; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Diagnosis, Differential; False Positive Reactions; Family; Female; Genetic Testing; Genetic Variation; Humans; Immunologic Tests; Infant, Newborn; Medical History Taking; Neonatal Screening; Sweat; Trypsinogen

To evaluate the performance of a new cystic fibrosis (CF) newborn screening algorithm, comprised of immunoreactive trypsinogen (IRT) in first (24-48 hours of life) and second (7-14 days of life) dried blood spot plus DNA on second dried blood spot, over existing algorithms.. A retrospective review of the IRT/IRT/DNA algorithm implemented in Colorado, Wyoming, and Texas.. A total of 1 520 079 newborns were screened, 32 557 (2.1%) had abnormal first IRT; 8794 (0.54%) on second. Furthermore, 14 653 mutation analyses were performed; 1391 newborns were referred for diagnostic testing; 274 newborns were diagnosed; and 201/274 (73%) of newborns had 2 mutations on the newborn screening CFTR panel. Sensitivity was 96.2%, compared with sensitivity of 76.1% observed with IRT/IRT (105 ng/mL cut-offs, P < .0001). The ratio of newborns with CF to heterozygote carriers was 1:2.5, and newborns with CF to newborns with CFTR-related metabolic syndrome was 10.8:1. The overall positive predictive value was 20%. The median age of diagnosis was 28, 30, and 39.5 days in the 3 states.. IRT/IRT/DNA is more sensitive than IRT/IRT because of lower cut-offs (∼97 percentile or 60 ng/mL); higher cut-offs in IRT/IRT programs (>99 percentile, 105 ng/mL) would not achieve sufficient sensitivity. Carrier identification and identification of newborns with CFTR-related metabolic syndrome is less common in IRT/IRT/DNA compared with IRT/DNA. The time to diagnosis is nominally longer, but diagnosis can be achieved in the neonatal period and opportunities to further improve timeliness have been enacted. IRT/IRT/DNA algorithm should be considered by programs with 2 routine screens.

Topics: Algorithms; Biomarkers; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Dried Blood Spot Testing; Female; Follow-Up Studies; Genetic Markers; Genetic Testing; Humans; Immunologic Tests; Infant, Newborn; Male; Mutation; Neonatal Screening; Predictive Value of Tests; Retrospective Studies; Sensitivity and Specificity; Trypsinogen; United States

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Humans; Infant, Newborn; Neonatal Screening; Trypsinogen

In cystic fibrosis newborn screening (CFNBS), immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP) can be used as screening parameters. We evaluated the IRT×PAP product as second-tier parameter in CFNBS in newborns with elevated IRT.. Data on 410,111 screened newborns including 78 patients with classical cystic fibrosis (CF) from two European centers were retrospectively analyzed by discrimination analysis to identify a screening protocol with optimal cutoffs. We also studied differences in PAP measurement methods and the association of IRT and PAP with age.. PAP values differed systematically between fluorometric and photometric assays. The IRT×PAP product showed better discrimination for classical CF than PAP only as second-tier screening parameter (p<0.001). In CF patients, IRT decreased while PAP values remained high over years. In newborns without CF, IRT decreased after birth over weeks while PAP increased within days.. The IRT×PAP product performs well as second-tier cutoff parameter for CFNBS. Screening quality parameters depend on the analytic method and on age at blood collection.

Topics: Chemistry Techniques, Analytical; Cystic Fibrosis; Female; Humans; Infant, Newborn; Male; Neonatal Screening; Pancreatitis-Associated Proteins; Retrospective Studies; Sensitivity and Specificity; Trypsinogen

Previous cost-effectiveness studies using data from the literature showed that newborn screening for cystic fibrosis (NBSCF) is a good economic option with positive health effects and longer survival.. We used primary data to compare cost-effectiveness of four screening strategies for NBSCF, i.e. immunoreactive trypsinogen-testing followed by pancreatitis-associated protein-testing (IRT-PAP), IRT-DNA, IRT-DNA-sequencing, and IRT-PAP-DNA-sequencing, each compared to no-screening. A previously developed decision analysis model for NBSCF was fed with model parameters mainly based on a study evaluating two novel screening strategies among 145,499 newborns in The Netherlands.. The four screening strategies had cost-effectiveness ratios varying from €23,600 to €29,200 per life-year gained. IRT-PAP had the most favourable cost-effectiveness ratio. Additional life-years can be gained by IRT-DNA but against higher costs. When treatment costs reduce with 5% due to early diagnosis, screening will lead to financial savings.. NBSCF is as an economically justifiable public health initiative. Of the four strategies tested IRT-PAP is the most economic and this finding should be included in any decision making model, when considering implementation of newborn screening for CF.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Cost-Benefit Analysis; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Decision Support Techniques; Genetic Testing; Humans; Infant, Newborn; Lectins, C-Type; Mutation; Neonatal Screening; Netherlands; Pancreatitis-Associated Proteins; Sensitivity and Specificity; Trypsinogen

Newborn screening strategies for cystic fibrosis (CF) are run worldwide, and aim at the early detection of the disorder to significantly improve the quality of life. Elevated levels of immunoreactive trypsinogen (IRT) represent a high likelihood for the screened child to be affected with CF. However, the specificity of IRT is low. The objective of this study was to assess the screening program in the Balearic Islands during the past 14 years.. We evaluated all results of the screening program after 14 years, by considering all changes in the protocol and assessing the number of positive samples, the mutations detected, the number of sweat tests performed, the incidence of CF and the presence of false-negative cases.. Despite a great variability among the different Balearic Islands, the global incidence of CF was 1:6059 for the 14 years assessed. The incidence in the smaller islands is about 5 times higher than in Majorca (1:2376 versus 1:10,613). After different changes in the protocol, an IRT cut-off value of 60 ng/mL was established. The two most common mutations are ΔF508 and G542X, in accordance with other geographical regions.. The changes in the protocol helped reduce the number of sweat tests performed without any increase in the false-negative rate.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Humans; Infant, Newborn; Molecular Diagnostic Techniques; Mutation, Missense; Neonatal Screening; Outcome Assessment, Health Care; Quality Improvement; Spain; Trypsinogen

To test the hypothesis that multiple constituents of the apical plasma membrane residing alongside the causal cystic fibrosis (CF) transmembrane conductance regulator protein, including known CF modifiers SLC26A9, SLC6A14, and SLC9A3, would be associated with prenatal exocrine pancreatic damage as measured by newborn screened (NBS) immunoreactive trypsinogen (IRT) levels.. NBS IRT measures and genome-wide genotype data were available on 111 subjects from Colorado, 37 subjects from Wisconsin, and 80 subjects from France. Multiple linear regression was used to determine whether any of 8 single nucleotide polymorphisms (SNPs) in SLC26A9, SLC6A14, and SLC9A3 were associated with IRT and whether other constituents of the apical plasma membrane contributed to IRT.. In the Colorado sample, 3 SLC26A9 SNPs were associated with NBS IRT (min P=1.16×10(-3); rs7512462), but no SLC6A14 or SLC9A3 SNPs were associated (P>.05). The rs7512462 association replicated in the Wisconsin sample (P=.03) but not in the French sample (P=.76). Furthermore, rs7512462 was the top-ranked apical membrane constituent in the combined Colorado and Wisconsin sample.. NBS IRT is a biomarker of prenatal exocrine pancreatic disease in patients with CF, and a SNP in SLC26A9 accounts for significant IRT variability. This work suggests SLC26A9 as a potential therapeutic target to ameliorate exocrine pancreatic disease.

Topics: Antiporters; Biomarkers; Cell Membrane; Colorado; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; France; Genetic Predisposition to Disease; Genotype; Humans; Infant, Newborn; Linear Models; Male; Mutation; Neonatal Screening; Pancreas, Exocrine; Polymorphism, Single Nucleotide; Quality Control; Sulfate Transporters; Trypsinogen; Wisconsin

Evidence from recent studies suggests that IRT/PAP protocols may be successfully used as a purely biochemical newborn screening (NBS) for cystic fibrosis (CF) that does not require genetic screening. However, the experience with the performance of different IRT/PAP protocols remains limited. In this study, we evaluated the performance of IRT/PAP-based CF-NBS used in two German regions between 2008 and 2013 in a large cohort.. In both regions slightly different IRT/PAP protocols were used to screen newborns for CF. In contrast to the original IRT/PAP protocol published by Sarles et al., both German protocols contained an IRT-dependent safety net strategy (CF-NBS positive, if IRT≥99.9th percentile). Positive rating of the screening result led to confirmatory diagnostics using sweat chloride testing and clinical assessment.. A total of 328,181 newborns were tested with IRT/PAP in Germany within 5 years. 639 of these newborns (0.19%) were tested positive, and 60 infants were diagnosed with CF leading to a sensitivity of 0.968 and a PPV (positive predictive value) of 0.097. Compared to IRT/DNA protocols, the PPV of IRT/PAP is lower, but PAP used as second tier test has the advantage of a lower detection rate of healthy carriers and CF patients with equivocal results.. Our results obtained in a large cohort of ∼330,000 newborns support the use of a purely biochemical IRT/PAP protocol as an acceptable alternative when genetic CF-NBS has to be avoided.

Topics: Antigens, Neoplasm; Biomarkers; Biomarkers, Tumor; Cohort Studies; Cystic Fibrosis; Female; Germany; Humans; Infant; Infant, Newborn; Lectins, C-Type; Male; Neonatal Screening; Pancreatitis-Associated Proteins; Sensitivity and Specificity; Trypsinogen

Newborn screening for Cystic Fibrosis (CF) began in New York in October, 2002 using immunoreactive trypsinogen (IRT)/DNA methodology. Infants with at least one CFTR mutation or very high IRT and no mutations (VHIRT) are referred for sweat testing. In a preliminary analysis, we noted a very low positive predictive value (PPV) and preponderance of Hispanic infants in the group of infants with CF referred for VHIRT, which led to a decision to revise, but not eliminate, the VHIRT category. Automatic referral for specimens with VHIRT collected on the day of birth was eliminated, and the VHIRT threshold was raised from 0.2% to 0.1%. In this report, we describe outcomes from VHIRT referrals among 2.4 million infants screened between March 2003 and February 2013. Following the algorithm change, referrals decreased by 37.8% overall (annual mean 1,485 vs. 923), and the VHIRT PPV improved (0.6-1.0%). The number of infants diagnosed has remained consistent at 1 in 4,400 births. The proportion of Black/Hispanic/Asian/Other infants with confirmed CF, CFTR-related metabolic syndrome (CRMS), or possible CF/CRMS was 21.3% in infants with 1-2 mutations, but 75.8% in the VHIRT group. In conclusion, although the PPV among VHIRT referrals remains low, had this category never been implemented, 24 infants with confirmed CF, and 9 infants with CRMS or possible CF/CRMS, most of whom were Hispanic, would have been missed over the 10 years. Information from this study may be helpful in assessing the need for the VHIRT category and algorithm changes in other screening programs.

Topics: Algorithms; Biomarkers; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Mutation; Neonatal Screening; New York; Predictive Value of Tests; Referral and Consultation; Trypsinogen

This article describes the methods used and the program performance results for the first 5 years of newborn screening for cystic fibrosis (CF) in California.. From July 16, 2007, to June 30, 2012, a total of 2,573,293 newborns were screened for CF by using a 3-step model: (1) measuring immunoreactive trypsinogen in all dried blood spot specimens; (2) testing 28 to 40 selected cystic fibrosis transmembrane conductance regulator (CFTR) mutations in specimens with immunoreactive trypsinogen values ≥62 ng/mL (top 1.6%); and (3) performing DNA sequencing on specimens found to have only 1 mutation in step 2. Infants with ≥2 mutations/variants were referred to CF care centers for diagnostic evaluation and follow-up. Infants with 1 mutation were considered carriers and their parents offered telephone genetic counseling.. Overall, 345 CF cases, 533 CFTR-related metabolic syndrome cases, and 1617 carriers were detected; 28 cases of CF were missed. Of the 345 CF cases, 20 (5.8%) infants were initially assessed as having CFTR-related metabolic syndrome, and their CF diagnosis occurred after age 6 months (median follow-up: 4.5 years). Program sensitivity was 92%, and the positive predictive value was 34%. CF prevalence was 1 in 6899 births. A total of 303 CFTR mutations were identified, including 78 novel variants. The median age at referral to a CF care center was 34 days (18 and 37 days for step 2 and 3 screening test-positive infants, respectively).. The 3-step model had high detection and low false-positive levels in this diverse population.

Topics: Algorithms; California; Child, Preschool; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Genetic Testing; Humans; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; Predictive Value of Tests; Prevalence; Sensitivity and Specificity; Trypsinogen

In recent years different IRT/PAP protocols have been evaluated, but the individual performance remains unclear. To optimize the IRT/PAP strategy we compared protocols from three regional CF newborn screening centers (Heidelberg, Dresden, and Prague).. We evaluated the effect of elevating the IRT-cut-off from 50 to 65 μg/l (~97.5th to ~99.0th percentile), the need of a failsafe protocol (FS, IRT ≥ 99.9th percentile) and the relative performance using either two IRT-dependent PAP-cut-offs or one PAP-cut-off.. Elevation of the IRT cut-off to 65 μg/l (~99.0th percentile) increased the PPV significantly (Dresden: 0.065 vs. 0.080, p < 0.0001, Prague: 0.052 vs. 0.074, p < 0.0001) without reducing sensitivity. All three IRT/PAP protocols showed a trend towards a higher sensitivity with FS than without and when using one PAP-cut-off instead of two IRT-dependent PAP-cut-offs.. For best performance we suggest an IRT/PAP protocol with an IRT-cut-off close to the 99.0th percentile, FS, and a single PAP-cut-off.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Chemistry, Clinical; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Dried Blood Spot Testing; Europe; Genetic Testing; Humans; Infant, Newborn; Lectins, C-Type; Neonatal Screening; Pancreatitis-Associated Proteins; Prospective Studies; Retrospective Studies; Sensitivity and Specificity; Trypsinogen

Early detection of cystic fibrosis (CF) by newborn screening (NBS) reduces the rate of avoidable complications. NBS protocols vary by jurisdiction and the cost effectiveness of these different protocols is debated.. To compare the cost effectiveness of various CF NBS options.. A Markov model was built to simulate the cost effectiveness of various CF-NBS options for a hypothetical CF-NBS program over a 5-year time horizon assuming its integration into an existing universal NBS program. NBS simulated options were based on a combination of tests between the two commonly used immunoreactive trypsinogen (IRT) cutoffs (96th percentile and 99.5th percentile) as first tier tests, and, as a second tier test, either a second IRT, pancreatic-associated protein (PAP) or CFTR mutation panels. CFTR mutation panels were also considered as an eventual third tier test. Data input parameters used were retrieved from a thorough literature search. Outcomes considered were the direct costs borne by the Quebec public health care system and the number of cases of CF detected through each strategy, including the absence of screening option.. IRT-PAP with an IRT cutoff at the 96th percentile is the most favorable option with a ratio of CAD$28,432 per CF case detected. The next most favorable alternative is the IRT1-IRT2 option with an IRT1 cutoff at the 96th percentile. The no-screening option is dominated by all NBS screening protocols considered. Results were robust in sensitivity analyses.. This study suggests that NBS for cystic fibrosis is a cost-effective strategy compared to the absence of NBS. The IRT-PAP newborn screening algorithm with an IRT cutoff at the 96th percentile is the most cost effective NBS approach for Quebec.

Topics: Algorithms; Antigens, Neoplasm; Biomarkers; Biomarkers, Tumor; Child, Preschool; Computer Simulation; Cost-Benefit Analysis; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Testing; Humans; Infant; Infant, Newborn; Lectins, C-Type; Markov Chains; Neonatal Screening; Pancreatitis-Associated Proteins; Sensitivity and Specificity; Trypsinogen

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Carrier Screening; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Trypsinogen

French health authorities promoted a study on 553,167 newborns comparing the performances of IRT/DNA and IRT/PAP for CF newborn screening.. In parallel to IRT/DNA, PAP was assayed in newborns with IRT>50 μg/L. Provisional PAP cutoffs at 3.0 μg/L when 50100 were used. Positive newborns were subjected to sweat test. Optimal cutoffs were established by a non-inferiority method.. 95 CF newborns were identified (83 classical forms (ClF), including 9 meconium ileus (MI), and 12 atypical (mild) forms (AF) Of them, IRT/DNA identified 85 (73 ClF including 5 MI and 12 AF). PAP cutoffs at 1.8 μg/L when 50< IRT<100 μg/L and 0.6 μg/L when IRT>100 μg/L would identify 82 CF: 77 ClF, including 8 MI, and 5 AF. The number of sweat tests was 314 and 1039 in the IRT/DNA and IRT/PAP strategies, respectively.. Using the optimal cutoffs, the sensitivity of the IRT/PAP strategy would not be inferior to that of IRT/DNA if identification of MF is not required.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA; DNA Mutational Analysis; Female; Follow-Up Studies; Genetic Testing; Humans; Infant, Newborn; Lectins, C-Type; Male; Mutation; Neonatal Screening; Pancreatitis-Associated Proteins; Retrospective Studies; Trypsinogen

Switzerland introduced newborn screening (NBS) for CF in 2011, using an IRT/DNA/IRT protocol. This paper describes the results of the first year and compares two versions of the protocol with different IRT cut-offs, particularly effects on recall rate, sensitivity and specificity.. IRT cut-offs were >45 ng/ml (99.0th percentile) in period 1 (months 1-4) and >50 ng/ml (99.2nd percentile) in period 2 (months 5-12). In period 2 we abstained from recalls when none of the 7 most common CF mutations were detected and IRT was <60 ng/ml.. In periods 1 and 2, 26,535 and 56,663 tests were performed. Recall rates were 0.94% and 0.48%, respectively (p<0.001), PPV increased from 23% to 47% (p=0.024) and sensitivity was 90% and 100%.. Raising initial IRT cut-off from the 99.0th to the 99.2nd percentile and abstaining from recalls for children with an IRT<60 ng/ml and carrying no major CFTR mutation significantly reduced the recall rate without affecting sensitivity.

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Humans; Infant, Newborn; Neonatal Screening; Pilot Projects; Sensitivity and Specificity; Sweat; Switzerland; Trypsinogen

We performed a pilot study of neonatal screening for cystic fibrosis (CF) in order to introduce it to the national screening program in Serbia.. Immunoreactive trypsinogen (IRT) concentrations were analyzed in dried blood spot samples. Patients were recalled for repeated measurements in case of high IRT levels. Persisting high IRT levels resulted in DNA testing for the 29 most common mutations in the CF transmembrane regulator (CFTR) gene (IRT/IRT/DNA method). Sweat chloride measurements and clinical assessment were further performed for newly diagnosed patients.. Of 1000 samples, three were initially positive and were further analyzed for the presence of the most common CFTR mutations in the Serbian population. DNA analysis revealed two patients being homozygous for F508del mutation. One sample was false positive, as the genetic test proved to be negative and associated with normal sweat chloride concentration and unremarkable clinical presentation.. The results of our pilot study justified the expanding of the routine neonatal screening program in Serbia with CF. Data could be used in future in order to obtain accurate incidence of CF and carrier prevalence in our country.

Topics: Cystic Fibrosis; DNA; Female; Genetic Testing; Humans; Incidence; Infant, Newborn; Male; Mutation; Neonatal Screening; Pilot Projects; Prevalence; Retrospective Studies; Serbia; Trypsinogen

Topics: Cystic Fibrosis; False Negative Reactions; Humans; Infant, Newborn; Neonatal Screening; Prevalence; Sensitivity and Specificity; Trypsinogen; United States

Newborn screening (NBS) for CF has become widespread, although there are multiple strategies. Little is known about outcomes such as age of diagnosis after different NBS methods.. We used the U.S. Cystic Fibrosis Foundation Patient Registry to identify infants with CF born between 2001 and 2008 in states that utilized NBS. We compared ages at diagnosis, genotyping, sweat test, and first visit to a CF Centre between states that used serial immunoreactive trypsinogen (IRT/IRT) levels and states that used IRT and DNA analysis (IRT/DNA).. We identified 1288 infants with CF. Compared to infants born in IRT/IRT states, infants born in IRT/DNA states were younger at the time of diagnosis (median 2.3 weeks versus 4.0 weeks in IRT/IRT states, p<0.001), genotyping (0.7 weeks versus 5.3 weeks, p<0.001), and initial CF Centre visit (5.9 weeks versus 7.7 weeks, p=0.008).. Although there is room to improve outcomes with both strategies, infants born in IRT/DNA states have treatment initiated at a younger age than infants born in IRT/IRT states.

Topics: Cystic Fibrosis; DNA Mutational Analysis; Genetic Carrier Screening; Genotyping Techniques; Humans; Infant; Infant, Newborn; Neonatal Screening; Sweat; Trypsinogen

We examined the relation between the number of (TG) repeats at the (IVS8)-(TG)m(T)5 locus of the CFTR gene with neonatal serum immunoreactive trypsinogen (IRT) and sweat chloride (SC) concentrations in hypertrypsinogenemic infants with genotype ΔF508-9T/5T identified by California cystic fibrosis newborn screening. SC and IRT distributions increased with increasing (TG) repeats.

Topics: California; Child, Preschool; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA; DNA Mutational Analysis; Female; Genotype; Humans; Incidence; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; Sweat; Trypsinogen

To compare three cystic fibrosis (CF) newborn screening strategies used in Victoria since 1989.. Retrospective review of newborn screening and clinical records for people with CF born in Victoria between 1989 and 2008 to compare screening strategies: repeat immunoreactive trypsinogen (IRT) testing (IRT/IRT, 1989-1990), IRT and p.F508del mutation analysis (IRT/p.F508del, 1991-2006) and IRT with analysis of 12 CFTR mutations (IRT/12 mutations, 2007-2008).. Total number of infants screened, people identified with CF (by screening or clinical diagnosis), number of CF-affected terminations of pregnancy, and number of carriers detected.. There were 420 people born with CF (live-birth prevalence, 1/3139; 95% CI, 1/2853-1/3462) and 78 CF-affected pregnancy terminations (overall prevalence, 1/2647; 95% CI, 1/2425-1/2896). Of the babies born with CF, 283 (67.4%) were detected by newborn screening alone, 61 (14.5%) had meconium ileus, 33 (7.9%) had a family history of CF, nine (2.1%) were diagnosed antenatally, and 34 (8.1%) were missed by screening (17 missed because IRT level was < 99th percentile, two with repeat IRT level not elevated, 14 without a screened CFTR mutation, and one with missing data). The sensitivities of the protocols were 86.6% for IRT/IRT, 89.9% for IRT/p.F508del, and 95.8% for IRT/12 mutations. Including 12 mutations in the analysis detected one patient who would otherwise have been missed and, had this protocol been implemented from 1989, it would have detected four others.. Most babies with CF without meconium ileus, a family history or antenatal diagnosis are detected by newborn screening. Despite improved sensitivity with the 12-mutation analysis, most infants detected would have been diagnosed using the IRT/p.F508del protocol.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA; DNA Mutational Analysis; Female; Follow-Up Studies; Genetic Testing; Humans; Infant, Newborn; Male; Mutation; Neonatal Screening; Pregnancy; Prevalence; Prognosis; Retrospective Studies; Sweat; Time Factors; Trypsinogen; Victoria

Because cystic fibrosis can be difficult to diagnose and treat early, newborn screening programs have rapidly developed nationwide but methods vary widely. We therefore investigated the costs and consequences or specific outcomes of the 2 most commonly used methods.. With available data on screening and follow-up, we used a simulation approach with decision trees to compare immunoreactive trypsinogen (IRT) screening followed by a second IRT test against an IRT/DNA analysis. By using a Monte Carlo simulation program, variation in the model parameters for counts at various nodes of the decision trees, as well as for costs, are included and applied to fictional cohorts of 100 000 newborns. The outcome measures included the numbers of newborns given a diagnosis of cystic fibrosis and costs of screening strategy at each branch and cost per newborn.. Simulations revealed a substantial number of potential missed diagnoses for the IRT/IRT system versus IRT/DNA. Although the IRT/IRT strategy with commonly used cutoff values offers an average overall cost savings of $2.30 per newborn, a breakdown of costs by societal segments demonstrated higher out-of-pocket costs for families. Two potential system failures causing delayed diagnoses were identified relating to the screening protocols and the follow-up system.. The IRT/IRT screening algorithm reduces the costs to laboratories and insurance companies but has more system failures. IRT/DNA offers other advantages, including fewer delayed diagnoses and lower out-of-pocket costs to families.

Topics: Algorithms; Combined Modality Therapy; Cost-Benefit Analysis; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Decision Trees; Diagnostic Errors; DNA Mutational Analysis; Female; Follow-Up Studies; Genetic Carrier Screening; Genetic Counseling; Health Care Costs; Health Expenditures; Humans; Infant, Newborn; Male; Monte Carlo Method; Neonatal Screening; Program Evaluation; Trypsinogen

Newborn screening (NBS) for Cystic Fibrosis (CF) has been introduced in many countries, but there is no ideal protocol suitable for all countries. This retrospective study was conducted to evaluate whether the planned two step CF NBS with immunoreactive trypsinogen (IRT) and 7 CFTR mutations would have detected all clinically diagnosed children with CF in Switzerland.. IRT was measured using AutoDELFIA Neonatal IRT-Kit in stored NBS cards.. Between 2006 and 2009, 66 children with CF were reported, 4 of which were excluded for various reasons (born in another country, NBS at 6 months, no informed consent). 98% (61/62) had significantly higher IRT compared to matched control group. There was one false negative IRT result in an asymptomatic child with atypical CF (normal pancreatic function and sweat test).. All children but one with atypical CF would have been detected with the planned two step protocol.

Topics: Algorithms; Child, Preschool; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Dried Blood Spot Testing; Female; Humans; Infant; Infant, Newborn; Male; Neonatal Screening; Reproducibility of Results; Retrospective Studies; Switzerland; Trypsinogen

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Cystic Fibrosis; Female; Humans; Lectins, C-Type; Male; Neonatal Screening; Pancreatitis-Associated Proteins; Trypsinogen

On May 23-24, 2011, a workshop entitled "Immunoreactive Trypsinogen (IRT) as a Biomarker for Cystic Fibrosis: Technical Issues and Challenges" was held in Annapolis, Maryland. The two-day workshop was co-hosted by the National Newborn Screening and Genetics Resource Center, Austin, Texas, and the Association of Public Health Laboratories, Silver Spring, Maryland, in collaboration with the Health Resources and Services Administration and the Centers for Disease Control and Prevention. Participants included nearly 40 representatives from U.S. state public health and commercial laboratories performing newborn dried blood spot screening tests for cystic fibrosis (CF), the federal government, academic research institutions, and commercial vendors of products used in newborn screening. Representatives from selected European CF newborn screening programs were also present. The workshop focused on identifying key IRT testing issues and mechanisms for achieving their resolution and laboratory harmonization in order to reduce, or eliminate completely, the late identified CF cases following a negative newborn screen. Informative findings are reported, their impacts on improving IRT screening are described, and their implications are discussed.

Topics: Biomarkers; Cystic Fibrosis; Dried Blood Spot Testing; Genetic Testing; Humans; Trypsinogen

Newborn screening for cystic fibrosis (CF) relies on the measurement of immunoreactive trypsinogen (IRT) originating from the pancreas. The Norfolk, Suffolk and Cambridgeshire screening programme initially exploited the persistent increase in IRT seen in CF (IRT-IRT protocol) and later changed to include mutation analysis as a second tier test (IRT-DNA-IRT protocol).. During a 30 year period 582 966 babies have been screened by IRT-IRT and 147 764 by IRT-DNA-IRT (total 730730), resulting in 296 screen positive cases of CF and 29 false negatives (including 10 false negatives with meconium ileus). Ten missed CF cases were pancreatic insufficient, however all were diagnosed before their first birthday, suggesting that a false negative result did not forestall appropriate clinical investigation. The IRT-DNA-IRT protocol had a much improved positive predictive value (PPV) of 85.9% compared to 67.3% for IRT-IRT, excluding CF babies with meconium ileus. The PPVs increased to 82.2% and 98.2% respectively if only well, term babies were considered. The main factor to account for this improvement in PPV has probably been the incorporation of DNA analysis in the second tier testing.. The diagnosis of screen-positive babies proved difficult in a minority of cases with the classification of some patients changing with evolving phenotype. Our results illustrate the importance of collecting outcome data over a long time period for accurate assessment of the screening programme. This study provides evidence that newborn screening for CF is a valid undertaking that detects 95% of unsuspected CF cases presenting before 3 years of age.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA; DNA Mutational Analysis; Genetic Testing; Humans; Incidence; Infant, Newborn; Mutation; Neonatal Screening; Predictive Value of Tests; Sensitivity and Specificity; Trypsinogen

Michigan's Newborn Screening (NBS) Program began statewide screening for cystic fibrosis (CF) in October 2007. Confirmatory sweat testing is performed in infants having initial immunoreactive trypsinogen concentrations ≥ 99.8th percentile or ≥ 96 th percentile and at least one CF mutation identified by DNA analysis. Some infants fail to produce a sufficient quantity of sweat (QNS-quantity not sufficient) to test for CF, meaning disease confirmation is delayed and sweat testing is later repeated. In this study, we evaluate predictors of QNS results. Information from the linked birth certificates and NBS diagnostic confirmation data were used. The study population was resident infants born in Michigan in 2008 who underwent a sweat test. Bivariate analyses revealed that preterm birth, low birth weight, CF care center, and race were significantly associated with QNS sweat testing results. Adjusted analyses indicated that preterm infants were 2.4 times more likely to have QNS results (95% CI 0.9, 6.4). When age at time of test, accounting for gestational age (gestational age at delivery plus postdelivery age of life=corrected age), was used in the multivariable model, infants <39 weeks were 7.4 times more likely to have QNS results (95% CI 2.5, 21.8). Waiting to sweat test until an infant is aged 39 weeks or more (corrected age) would likely reduce the rate of QNS results, thereby reducing the burden of repeat sweat testing on families and healthcare providers. Further research is necessary to understand the impact of potential delays in diagnosis/treatment relative to postponing sweat testing.

Topics: Cohort Studies; Cystic Fibrosis; Female; Humans; Infant; Infant, Newborn; Male; Michigan; Retrospective Studies; Risk Factors; Sweating; Trypsinogen

To investigate variation in immunoreactive trypsinogen (IRT) concentrations by race, sex, birth weight, and gestational age and their implications for the use of percentile-based cutoffs for cystic fibrosis (CF) newborn screening (NBS) programs.. This cross-sectional population-based study of resident infants screened in Michigan investigates associations between demographic and perinatal variables and IRT concentrations after controlling for covariates. This study also analyzed how 96th and 99.8th IRT concentration percentiles values calculated by Michigan NBS vary by demographic and perinatal factors. Characteristics of infants having high (≥99.8th percentile) IRT concentrations and negative DNA tests are also explored.. IRT mean concentrations and percentiles vary significantly by race, birth weight, gestational age, and to a lesser degree by sex. The greatest variation in mean IRT concentrations was observed among racial categories; black infants had an adjusted mean concentration of 36 ng/ml and Asian/Pacific Islander infants had a mean concentration of 25 ng/ml compared to an average concentration of 28 ng/ml in white infants and infants of other races.. Variation in IRT concentrations resulted in the over-representation of certain groups referred for secondary testing, particularly referrals for sweat testing based on very high (≥99.8th percentile) concentrations alone, which is no longer recommended in Michigan. Further research may be warranted to evaluate initial IRT cutoffs used for CF NBS.

Topics: Birth Weight; Cross-Sectional Studies; Cystic Fibrosis; Female; Gestational Age; Humans; Infant, Newborn; Male; Michigan; Neonatal Screening; Racial Groups; Trypsinogen

The diagnosis of cystic fibrosis (CF) is often delayed because of the nonspecificity of a wide variety of clinical symptoms at disease onset. Newborn screening for CF has been advocated to reduce delays in diagnosis, facilitating preventive care for early respiratory and nutritional involvement. According to American and European consensus and experience of existing programs, a Swiss Nationwide Cystic Fibrosis Newborn Screening Program started in January 2011. Screening strategy combines two steps: an immunoreactive trypsinogen assay and DNA mutation analysis in dried blood samples at day 4 (Guthrie cards).

Topics: Cystic Fibrosis; DNA Mutational Analysis; Humans; Infant, Newborn; Neonatal Screening; Predictive Value of Tests; Sensitivity and Specificity; Switzerland; Trypsinogen

An unavoidable outcome of cystic fibrosis newborn screening (CF NBS) programs is the detection of infants with an indeterminate diagnosis. The United States CF Foundation recently proposed the term cystic fibrosis transmembrane conductance regulator related metabolic syndrome (CRMS) to describe infants with elevated immunoreactive trypsinogen (IRT) on NBS who do not meet diagnostic criteria for CF. The objective of this study was to describe the clinical outcomes of infants with CRMS identified through an IRT/DNA algorithm. We reviewed the records of all infants with CRMS diagnosed at our CF Center from 2002 to 2010. We identified 12 infants, and compared them to 27 infants diagnosed with CF by NBS. Compared to CF patients, CRMS patients were more likely to be pancreatic sufficient as assessed by fecal elastase measurement (100% vs. 8%, P < 0.01). Their weight for age percentile was normal from birth. A positive oropharyngeal (OP) culture for Pseudomonas aeruginosa (Pa) was found in 25% of CRMS patients. One patient with the F508del/R117H/7T genotype was reassigned the diagnosis of CF after he had a positive OP culture for Pa, and his follow up sweat Cl at 1 year of life was 73 mmol/L. CF patients were more likely to receive oral antibiotics and be hospitalized for pulmonary symptoms. Our results indicate that CRMS patients can develop signs of CF disease, but have a milder clinical course than CF infants. Close initial monitoring of these patients is warranted. Pediatr. Pulmonol. 2011; 46:1079-1084. © 2011 Wiley Periodicals, Inc.

Topics: Anti-Bacterial Agents; Child, Preschool; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Feces; Female; Hospitalization; Humans; Infant; Infant, Newborn; Male; Metabolic Syndrome; Monitoring, Physiologic; Neonatal Screening; Oropharynx; Pancreatic Elastase; Pseudomonas aeruginosa; Pseudomonas Infections; Respiratory Tract Infections; Retrospective Studies; Sweat; Trypsinogen

Newborn screening is a public health policy program involving the centralized testing laboratory, infant and their family, primary care provider, and subspecialist for confirmatory testing and follow-up of abnormal results. Cystic fibrosis (CF) newborn screening has now been enacted in all 50 states and the District of Columbia and throughout many countries in the world. Although CF neonatal screening will identify the vast majority of infants with CF, there are many factors in the newborn screening system that can lead to a missed diagnosis of CF. To inform clinicians, this article summarizes the CF newborn screening system and highlights 14 factors that can account for a missed diagnosis of CF. Care providers should maintain a high suspicion for CF if there are compatible symptoms, regardless of the results of the newborn screening test. These factors in newborn screening programs leading to a missed diagnosis of CF present opportunities for quality improvement in specimen collection, laboratory analysis of immunoreactive tryspinogen (IRT) and CF mutation testing, communication, and sweat testing.

Topics: Chlorides; Cystic Fibrosis; Diagnostic Errors; Female; Humans; Infant; Infant, Newborn; Male; Neonatal Screening; Sensitivity and Specificity; Sweat; Trypsinogen

Since its beginnings, newborn screening for cystic fibrosis (CF) using an assay for immunoreactive trypsinogen (IRT) has been plagued by a high rate of false-positive results (screen positive, diagnosis negative), despite attempts to reduce this rate by use of altered cutoffs and second-tier DNA testing. IRT exists as 2 isoforms: IRT1 and IRT2, with IRT2 being more closely aligned with pancreatic disease, including CF. Assay standardization between programs is a continuing problem because the IRT assays currently in use variously recognize either 1 or both isoforms. Here we report the development of a multiplexed assay for both forms of IRT simultaneously.. Using 2 different Luminex bead sets, we developed assays for each IRT isoform separately and then combined them. Using the sum of IRT1 and IRT2 values (IRT1+IRT2), we compared the results with a CF kit currently in use.. In a sample set consisting of 16 cases confirmed positive for CF, we established a cutoff at >97 microg/L total IRT. Seven of 8 carriers with 1 CF mutation screen-positive by the standard method were also screen-positive by IRT1+IRT2. Of 32 cases screen-positive by standard IRT, 11 were screen-negative by IRT1+IRT2. None of these 11 cases had CF mutations identified by the screening program.. These data indicate that the multiplex method with specificity for 2 isoforms of IRT has performance comparable to that of a standard IRT method and the advantage of improved standardization by detection of the 2 isoforms.

Topics: Cystic Fibrosis; Humans; Immunoassay; Infant, Newborn; Neonatal Screening; Protein Isoforms; Trypsinogen

Newborn screening (NBS) for cystic fibrosis (CF) offers the opportunity for early diagnosis and improved outcomes in patients with CF and has been universally available in the state of Massachusetts since 1999 using an immunoreactive trypsinogen (IRT)-DNA algorithm. Ideally, CF NBS is incorporated as part of an integrated NBS system that allows for comprehensive and coordinated education, laboratory screening, clinical follow-up, and evaluation so that evidence-based data can be used to maximize quality improvements and optimize the screening algorithm. The New England Newborn Screening Program (NENSP) retrospectively analyzed Massachusetts's CF newborn screening data that yielded decisions to eliminate a screen-positive category, maintain the IRT cutoff value that prompts the second tier DNA testing, and communicate CF relative risk to primary care providers (PCPs) based on categorization of positive CF NBS results.

Topics: Algorithms; Biomarkers; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Genetic Testing; Humans; Immunoassay; Infant, Newborn; Massachusetts; Mutation; Neonatal Screening; Predictive Value of Tests; Primary Health Care; Program Development; Program Evaluation; Quality Indicators, Health Care; Retrospective Studies; Sweat; Trypsinogen

Screening for cystic fibrosis (CF) was recently added to the neonatal screening programme in the Netherlands. Four patients with renal failure whose heel prick tests were positive for CF as defined by raised levels of immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP) are described. Both cystic fibrosis transmembrane conductance regulator (CFTR) DNA analysis and sweat tests were negative. Limited renal function can be a cause of false positive neonatal screening for CF using IRT and PAP.

Topics: Antigens, Neoplasm; Biomarkers; Biomarkers, Tumor; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; False Positive Reactions; Humans; Infant, Newborn; Lectins, C-Type; Male; Neonatal Screening; Pancreatitis-Associated Proteins; Renal Insufficiency; Trypsinogen

Ethical concerns and disadvantages of newborn screening (NBS) for cystic fibrosis (CF) related to genetic testing have raised controversies and impeded implementation of CF NBS in some countries. In the present study, we used a prospective and sequential immunoreactive trypsinogene (IRT)/pancreatitis-associated protein (PAP) strategy, with IRT as first and PAP as second tier, and validated this biochemical approach against the widely used IRT/DNA protocol in a population-based NBS study in southwest Germany.. Prospective quantitation of PAP and genetic analysis for the presence of four mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene most prevalent in southwest Germany (F508del, R553X, G551D, G542X) were performed in all newborns with IRT > 99.0th percentile. NBS was rated positive when either PAP was ≥1.0 ng/mL and/or at least one CFTR mutation was detected. In addition, IRT > 99.9th percentile was also considered a positive rating. Positive rating led to referral to a CF centre for testing of sweat Cl(-) concentration.. Out of 73,759 newborns tested, 98 (0.13%) were positive with IRT/PAP and 56 (0.08%) with IRT/DNA. After sweat testing of 135 CF NBS-positive infants, 13 were diagnosed with CF. Detection rates were similar for both IRT/PAP and IRT/DNA. One of the 13 diagnosed CF newborns had a PAP concentration <1.0 ng/mL.. Sequential measurement of IRT/PAP provides good sensitivity and specificity and allows reliable and cost-effective CF NBS which circumvents the necessity of genetic testing with its inherent ethical problems.

Topics: Antigens, Neoplasm; Biomarkers; Biomarkers, Tumor; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Enzyme-Linked Immunosorbent Assay; Genetic Testing; Germany; Humans; Infant, Newborn; Lectins, C-Type; Mutation; Neonatal Screening; Pancreatitis-Associated Proteins; Predictive Value of Tests; Program Evaluation; Prospective Studies; Sensitivity and Specificity; Sweat; Trypsinogen

To ensure that each newborn receives an equitable test of the highest possible sensitivity, we recognized the necessity to reassess immunoreactive trypsinogen and DNA issues in cystic fibrosis newborn screening algorithms. Our objectives included clarification of various factors that influence immunoreactive trypsinogen concentrations and resolution of long-standing questions about variations in immunoreactive trypsinogen levels among newborns.. Immunoreactive trypsinogen data on 660443 newborns who were born between July 1, 1994, and June 30, 2004, were abstracted from the Wisconsin State Laboratory of Hygiene databases and deidentified for analysis. Using a compiled data set, we analyzed various demographic characteristics to determine their role, if any, in immunoreactive trypsinogen variation. Specifically, season of birth, reagent lot, and birth weight were examined. Sensitivities of the most common cystic fibrosis newborn screening protocols, namely immunoreactive trypsinogen/immunoreactive trypsinogen and immunoreactive trypsinogen/DNA, were also investigated.. Mean and 95th percentile immunoreactive trypsinogen levels were shown to vary by both season and reagent lot number and affect sensitivity of the assay. Low birth weight infants had significantly higher immunoreactive trypsinogen values than normal birth weight infants. Sensitivities were also found to vary on the basis of the algorithm used, with the highest sensitivity of 96.2% calculated for an immunoreactive trypsinogen/DNA protocol with 23 cystic fibrosis transmembrane conductance regulator mutation analyses compared with 80.2% with the immunoreactive trypsinogen/immunoreactive trypsinogen method used in 9 states.. Floating, rather than fixed, cutoff values for the initial immunoreactive trypsinogen portion of any cystic fibrosis newborn screening protocol are generally necessary on the basis of the seasonal and reagent lot variations observed. Because of its lower sensitivity, immunoreactive trypsinogen/immunoreactive trypsinogen does not optimize detection of patients with cystic fibrosis.

Topics: Algorithms; Cystic Fibrosis; Female; Humans; Infant, Newborn; Male; Neonatal Screening; Sensitivity and Specificity; Trypsinogen

Most patients with cystic fibrosis (CF) have pancreatic insufficiency; however, 15% of the patients are pancreatic sufficient (PS). Several laboratory tests have been developed to distinguish between pancreatic insufficiency and PS. The gold standard to determine pancreatic function apart from direct pancreatic stimulation test is the 72-hour fecal fat excretion, expressed as coefficient of fat absorption (CFA). The aim was to test the correlation between 2 other tests, fecal elastase-1 and serum immunoreactive trypsinogen (IRT), as compared with fecal fat excretion.. 21 patients with CF-PS performed the 3 tests of fecal fat excretion, fecal elastase-1, and IRT. Correlation between the tests was evaluated by the kappa statistics test, sensitivity and specificity, and positive and negative predictive values.. CFA was abnormal in 5 patients, elastase was <200microg/g in 4 patients, and IRT was <20 ng/mL in 2 patients. The correlation between CFA and IRT was negative(kappa=-0.154), and between CFA and fecal elastase-1 was poor (kappa=0.213). The sensitivity, specificity, and positive and negative predictive values of IRT versus CFA were 0%, 88%, 0%, and 78%, and for fecal elastase-1 were 40%, 81%, 40%, and 81%, respectively.. In CF-PS, poor correlation was found between IRT, fecal elastase-1, and CFA, therefore neither fecal elastase-1 in the stool nor IRT in the serum reaches the sensitivity or the specificity of the fecal fat excretion. Thus, fecal fat excretion is required in patients with CF for evaluation of pancreatic function.

Topics: Adult; Cystic Fibrosis; Dietary Fats; Exocrine Pancreatic Insufficiency; Feces; Female; Humans; Infant; Male; Pancreas; Pancreatic Elastase; Sensitivity and Specificity; Trypsinogen

To evaluate an immunoreactive trypsinogen (IRT) IRT/IRT1 upward arrow/DNA algorithm, aimed at improving sensitivity while decreasing cystic fibrosis (CF) carrier identification.. New technologies allow the measurement of the second IRT level solely in infants with an elevated first IRT level. Specimens with an elevated second IRT level undergo mutation analysis. We tested the projected efficacy with retrospective data from Colorado.. All known infants with CF would have been identified with our proposed IRT cutoff points, and 3 would have been missed with our mutation panel. Two of 3 missed cases would have been identified by using a failsafe method (IRT >99.9th percentile), yielding a sensitivity rate of 99.7% (95% CI, 98.4-99.9). Estimated reduction in carrier detection was 80% compared with IRT/DNA.. IRT/IRT1 upward arrow/DNA appears to improve cystic fibrosis newborn screen sensitivity while decreasing carrier identification, providing an alternative to IRT/IRT in states that obtain 2 blood spots.

Topics: Algorithms; Cohort Studies; Colorado; Confidence Intervals; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Female; Genetic Predisposition to Disease; Genetic Testing; Heterozygote; Humans; Infant, Newborn; Male; Neonatal Screening; Probability; Retrospective Studies; Sensitivity and Specificity; Time Factors; Trypsinogen

Cystic fibrosis is one of the most common autosomal recessive hereditary diseases in the Caucasian population, with an incidence of 1:2000 to 1:3500 liveborns. More than 1000 mutations have been described with the most common being F508del. It has a prevalence of 23-55% within the Brazilian population. The lack of population-based studies evaluating the incidence of cystic fibrosis in São Paulo State, Brazil, and an analysis concerning the costs of implantation of a screening program motivated the present study. A total of 60,000 dried blood samples from Guthrie cards obtained from April 2005 to January 2006 for neonatal screening at 4 reference centers in São Paulo State were analyzed. The immunoreactive trypsinogen (IRT)/IRT protocol was used with the cut-off value being 70 ng/mL. A total of 532 children (0.9%) showed IRT >70 ng/mL and a 2nd sample was collected from 418 (80.3%) of these patients. Four affected children were detected at two centers, corresponding to an incidence of 1:8403. The average age at diagnosis was 69 days, and 3 of the children already showed severe symptoms of the disease. The rate of false-positive results was 95.2% and the positive predictive value for the test was 8%. The cost of detecting an affected subject was approximately US$8,000.00 when this cystic fibrosis program was added to an existing neonatal screening program. The present study clearly shows the difficulties involved in cystic fibrosis screening using the IRT/IRT protocol, particularly in a population with no long-term tradition of neonatal screening.

Topics: Biomarkers; Brazil; Cystic Fibrosis; Humans; Infant; Infant, Newborn; Neonatal Screening; Pilot Projects; Predictive Value of Tests; Trypsinogen

Through early detection, newborn screening (NBS)(1) for cystic fibrosis (CF) offers the opportunity for early intervention and improved outcomes. NBS programs screen for hypertrypsinogenemia, and most also identify mutations in the CF transmembrane conductance regulator (CFTR) gene. Individuals identified by NBS are diagnosed with CF if they have an elevated sweat chloride level or if they have inherited 2 disease-causing mutations in the CFTR gene. Mutations in the CFTR gene can cause CF, but not all CFTR mutations are disease-causing. The term CFTR-related metabolic syndrome (CRMS) is proposed to describe infants identified by hypertrypsinogenemia on NBS who have sweat chloride values <60 mmol/L and up to 2 CFTR mutations, at least 1 of which is not clearly categorized as a "CF-causing mutation," thus they do not meet CF Foundation guidelines for the diagnosis of CF. With what is now near-universal CF NBS in the United States, an increasing number of infants with CRMS are being identified. Given our inadequate knowledge of the natural history of CRMS, standards for diagnosis, monitoring, and treatment are absent. This document aims to help guide the monitoring and care of individuals with CRMS while our knowledge base on appropriate management evolves.

Topics: Adult; Age Factors; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant; Infant, Newborn; Metabolic Diseases; Syndrome; Trypsinogen

During the first 4 years of newborn screening (NBS) for Cystic Fibrosis (CF) in New York there was a statistically significant, twofold greater relative risk of an Immunoreactive Trypsinogen (IRT) level greater than 95% in African-American infants. The reason for this previously reported increase in IRT level in African-American infants is unclear. The positive predictive value of a screen positive result in this population was only 0.3%. The bulk of screen-positive African-American infants were in the top 0.2% (IRT) group, with no CF mutations isolated. Repeat IRT testing at 2-3 weeks of age may represent a suitable approach to decrease the false-positive rate in this population.

Topics: Black or African American; Cystic Fibrosis; False Positive Reactions; Female; Humans; Infant, Newborn; Male; Mass Screening; Predictive Value of Tests; Risk; Trypsinogen

Cystic fibrosis (CF) is a recessively inherited condition caused by mutation of the CFTR gene. Newborn infants with CF have raised levels of immuno-reactive trypsinogen (IRT) in their serum. Measurement of IRT in the first week of life has enabled CF to be incorporated into existing newborn screening (NBS) blood spot protocols. However, IRT is not a specific test for CF and NBS therefore requires a further tier of tests to avoid unnecessary referral for diagnostic testing. Following identification of the CFTR gene, DNA analysis for common CF-associated mutations has been increasingly used as a second tier test. The aim of this study was to survey the current practice of CF NBS programmes in Europe.. A questionnaire was sent to 26 regional and national CF NBS programmes in Europe.. All programmes responded. The programmes varied in number of infants screened and in the protocols employed, ranging from sweat testing all infants with a raised first IRT to protocols with up to four tiers of testing. Three different assays for IRT were used; in the majority (24) this was a commercially available kit (Delfia). A number of programmes employed a second IRT measurement in the 4th week of life (as the IRT is more specific at this point). Nineteen programmes used DNA analysis for common CFTR mutations on samples with a raised first IRT. Three programmes used a second IRT measurement on infants with just one recognised mutation to reduce the number of infants referred for sweat testing. Referral to clinical services was prompt and diagnosis was confirmed by sweat testing, even in infants with two recognised mutations in most programmes. Subsequent clinical pathways were less uniform. Multivariate analysis demonstrated a relationship between the age of diagnosis and the timing of the first IRT. More sweat tests were undertaken if the first IRT was earlier and the diagnosis was later.. Annually these programmes screen approximately 1,600,000 newborns for CF and over 400 affected infants are recognised. The findings of this survey will guide the development of European evidence based guidelines and may help new regions or nations in the development and implementation of NBS for cystic fibrosis.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Data Collection; Europe; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Practice Guidelines as Topic; Professional Practice; Trypsinogen

The neonatal screening protocol for cystic fibrosis (CF) is based on a first determination of blood immunoreactive trypsin (IRT1), followed by a first level genetic test that includes the 31 worldwide most common mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene (DNA31), and a second determination of blood immunoreactive trypsin (IRT2). This approach identifies, in addition to affected subjects, a high proportion of newborns with hypertrypsinaemia at birth, in whom only one mutation is identified and who have a negative or borderline sweat test and pancreatic sufficiency. Although it has been suggested that hypertrypsinaemia may be caused by a single CFTR mutation, whether such neonates should be merely considered as healthy carriers remains a matter of debate as hypertrypsinaemia at birth may be a biochemical marker of a CFTR malfunction because of a second mild mutation. We analyzed, by means of an extended sequencing protocol, 32 newborns who tested positive at an IRT1/DNA31/IRT2 screening protocol and in whom only one CFTR mutation was found. The results obtained demonstrate that 62.5% of these newborns were also carrying a second mild CFTR mutation. The high proportion of compound heterozygous subjects, combined with the results of a 4-year follow-up in nine of these subjects all of whom displaying initial CF clinical symptoms, suggest that it may be possible to use the IRT1/DNA31/IRT2 protocol of neonatal screening to identify newborns with atypical forms of CF. In view of these findings, an extended genetic search for subjects with compound heterozygosity and a periodic clinical assessment should be considered.

Topics: Child, Preschool; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Follow-Up Studies; Genetic Testing; Genotype; Heterozygote; Humans; Infant; Infant, Newborn; Neonatal Screening; Trypsin; Trypsinogen

Topics: Base Sequence; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Gene Deletion; Heterozygote; Humans; Ileal Diseases; Infant, Newborn; Intestinal Diseases; Meconium; Models, Genetic; Molecular Sequence Data; Mutation; Neonatal Screening; Trypsinogen

To investigate the immunoreactive trypsinogen (IRT) values above the usual 99th centile laboratory cut-off and determine the value of offering further testing to those infants with a markedly elevated IRT but no cystic fibrosis transmembrane regulator (CFTR) gene mutation identified by the screening programme.. All babies born in Victoria, Australia, between 1991 and 2003, were screened by IRT followed by CF gene mutation analysis.. Of the 806,520 babies born, 9268 with the highest IRT levels had CFTR mutation analysis. There were 123 DeltaF508 homozygotes and 703 heterozygotes (86 with CF, 617 carriers). A total of 8442 babies had no CFTR gene mutation, of whom 18 (0.21%) had CF. The total number of CF babies with IRT greater than the laboratory cut-off was 227 (2.4%). The IRT results of the CF patients were distributed normally, with the majority above the laboratory cut-off of newborn IRT results. There was no evidence of an excess of babies with CF in the very highest levels of IRT above the 99th centile.. Only a small proportion of babies with a neonatal IRT >99th centile have CF. Additional CF testing for infants with an elevated IRT but no CFTR gene mutation has an extremely low yield, no matter how high the IRT result.

Topics: Biomarkers; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; False Positive Reactions; Female; Genetic Testing; Heterozygote; Homozygote; Humans; Infant, Newborn; Male; Mutation; Neonatal Screening; Reference Values; Trypsinogen

Topics: Chlorides; Cystic Fibrosis; DNA Mutational Analysis; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Sweat; Trypsinogen; United States

In response to increasing numbers of states in the US that test newborn babies for cystic fibrosis (CF), the Newborn Screening Quality Assurance Programme initiated a pilot proficiency testing programme for immunoreactive trypsinogen (IRT), the biomarker for CF. Dried blood spot specimens (DBS) were used to evaluate the performance of laboratories that screen babies for CF.. DBS were prepared from human whole blood enriched with physiologically relevant levels of IRT. Various methods of making IRT-enriched DBS were used to optimize the recovery and stability of the biomarker, including preparation of DBS from either intact or lysed red blood cells, varying the timing of IRT addition to blood before dispensing onto filter paper, adding a protease inhibitor cocktail, and treating serum with charcoal before IRT enrichment. The recovery and stability of IRT in DBS were assessed. Newborn screening laboratories were offered the opportunity to test blind-coded DBS in the pilot PT programme.. IRT was stable in the filter paper matrix when stored for one year at either -20 degrees C or 4 degrees C. Fifty percent more IRT was recovered from DBS prepared with lysed red blood cells where the IRT was added to blood just before dispensing; however, protease inhibitors did not improve IRT recovery.. IRT in the DBS matrix is stable and can be shipped worldwide under ambient conditions. Optimal IRT recovery was achieved by adjustment of DBS production practices. Laboratories receiving specimens accurately measured IRT by a variety of commercial and in-house methods.

Topics: Charcoal; Cystic Fibrosis; Humans; Infant, Newborn; Mass Screening; Mutation; Neonatal Screening; Pilot Projects; Protease Inhibitors; Quality Control; Specimen Handling; Temperature; Trypsinogen; United States

Newborn screening (NBS) protocols for cystic fibrosis (CF) are the first regional population-based programs to incorporate DNA analysis into their procedures. Research about these programs can inform policy and practice regarding how best to counsel families with abnormal NBS results. The grounded theory method guided interviews with 33 families whose infants had abnormal CF NBS results. A dimensional analysis of these interviews provided a theoretical framework describing parents' preferences regarding counseling during their infant's sweat test appointment. This framework describes the contexts and characteristics of the two main dimensions of parents' preferences: factual information and emotional support. Factual information included learning about the probability of a CF diagnosis, CF disease facts, sweat test procedure, and CF genetics. Social support consisted of offering parents a choice about the timing and amount of CF information, showing empathy for their distress, instilling hope, personalizing counseling, and providing hospitality. This framework also explains the consequences of counseling that matched versus mismatched parental preferences in these domains. Counseling that matched parents preferences reduced parents' distress while mismatched counseling tended to increase parents' worry about their infant.

Topics: Adaptation, Psychological; Adolescent; Adult; Choice Behavior; Consumer Behavior; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Female; Follow-Up Studies; Genetic Carrier Screening; Genetic Counseling; Health Education; Humans; Infant; Infant, Newborn; Male; Middle Aged; Neonatal Screening; Parents; Referral and Consultation; Social Support; Sweat; Trypsinogen

To characterize the time course and physiologic significance of decline in serum immunoreactive trypsinogen (IRT) levels in infants with cystic fibrosis (CF) by mode of diagnosis and genotype, and to examine IRT heritability.. We studied longitudinal IRT measurements in 317 children with CF. We developed statistical models to describe IRT decline. Pancreatic disease severity (Mild or Severe) was assigned using CF genotype and was confirmed in 47 infants through fat malabsorption studies.. Infants with severe disease exhibited IRT decline with non-detectable levels typically seen by 5 years of age. Infants with mild disease exhibited a decline in the first 2 years, asymptomatically approaching a level greater than published norms. IRT and fecal fat were inversely correlated. IRT values in infants with meconium ileus (MI) were significantly lower than newborn-screened infants at birth. The high proportion of shared variation in predicted IRT values among sibling pairs with severe disease suggests that IRT is heritable.. IRT declines characteristically in infants with CF. Lower IRT values in newborns with MI suggest increased pancreatic injury. Furthermore, IRT is heritable among patients with severe disease suggesting genetic modifiers of early CF pancreatic injury. This study demonstrates heritability of a statistically modeled quantitative phenotype.

Topics: Biomarkers; Body Height; Body Weight; Chlorides; Cystic Fibrosis; DNA Mutational Analysis; Fats; Feces; Female; Follow-Up Studies; Genetic Predisposition to Disease; Genotype; Humans; Ileus; Infant, Newborn; Longitudinal Studies; Malabsorption Syndromes; Male; Neonatal Screening; Predictive Value of Tests; Severity of Illness Index; Sweat; Trypsinogen; Vitamins

Following cystic fibrosis (CF) neonatal screening implementation, a high frequency of heterozygotes has been reported among neonates with elevated immunoreactive trypsinogen (IRT) and normal sweat chloride levels. We studied the relationship between normal IRT values and CF heterozygosity: 10,000 neonates were screened for CF by IRT measurement and tested for 40 CF mutations; the 294 carriers detected were coupled with newborns negative to the same genetic testing, and the two groups' IRT levels compared. Heterozygotes had higher IRT levels than their controls (mean 35.32 vs. 27.58 microg/L, P<0.001). Even within normal trypsinogen range, the probability of being a CF carrier increases with neonatal IRT concentration.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Genetic Testing; Heterozygote; Humans; Immunoassay; Infant, Newborn; Italy; Mutation; Neonatal Screening; Pancreatic Function Tests; Trypsinogen

To describe the screening approaches and implementation strategies for cystic fibrosis newborn screening in the 12 programs that were offered in 11 states in 2002.. Telephone interviews conducted in the spring of 2003 with program representatives in the 11 states. Screening approaches were defined in four overlapping categories: state mandated screening, state-wide offering, hospital based screening, and screening with informed consent.. Screening was state mandated in seven states but was routinely offered to most infants in nine states. The primary care provider or hospital determined if screening was done in three states (four programs). Informed consent was explicitly documented in two states. In five programs, immunoreactive trypsinogen exclusively was used to identify at-risk infants. In seven programs, a second tier DNA test was also used, but these programs each had distinct strategies. In only two programs where DNA testing was performed and normal sweat tests indicated carrier status, were results routinely provided to parents "in person" at a CF center.. The diversity of approaches for screening approaches and strategies has advantages for future policy decisions, provided that data about the clinical and psychosocial impact of screening from these programs are collected and disseminated. As additional states determine that the resources are available, programs can be designed with a more favorable benefit/risk balance as a result of the successes and challenges faced by other states.

Topics: Cystic Fibrosis; Health Policy; Humans; Infant, Newborn; Informed Consent; Neonatal Screening; Predictive Value of Tests; Trypsinogen; United States

Topics: Blood Chemical Analysis; Cystic Fibrosis; Enzyme-Linked Immunosorbent Assay; Humans; Infant, Newborn; Neonatal Screening; Trypsinogen

The French Association for Neonatal Screening implemented cystic fibrosis neonatal screening (CF NBS) region by region in France, from the beginning of the year 2002 to early 2003. The program uses an immunoreactive trypsinogen/DNA testing algorithm on dried blood samples obtained at 3 days of age. Incorporation of DNA testing necessitated compliance with official regulations and French "bioethics" laws: the need for a written consent from the patient/guardian and specific circulation of the prescription, sample, and results. To fulfill these obligations, the Ethics and Genetics committee of the French Association for Neonatal Screening recommended that informed consent should be obtained for all neonates at birth by having the parents sign directly on the sampling paper. This study was designed to evaluate the effect of the educational efforts used to obtain informed consent on acceptance of CF NBS.. Data from the screening center in Lille, France, were analyzed to determine the rate of refusal of CF NBS in the 18 months after initiation of the informed consent process.. The number of refusals for CF NBS declined from 0.8% at the start of the program to 0.2% at the end of the first year of the new process for obtaining written consent.. Efforts to inform parents and professionals resulted in a significant decrease in the number of refusals for CF NBS.

Topics: Algorithms; Attitude to Health; Consent Forms; Cystic Fibrosis; DNA Mutational Analysis; Documentation; France; Genetic Counseling; Genetic Privacy; Health Education; Humans; Immunoassay; Infant, Newborn; Neonatal Screening; Parental Consent; Parents; Refusal to Participate; Teaching Materials; Trypsinogen

To describe the development and follow-up confirmatory results of the routine cystic fibrosis (CF) newborn screening (NBS) program in Wisconsin.. CF NBS has been performed on a routine clinical basis in Wisconsin since July 1994. The 2-tiered immunoreactive trypsinogen (IRT)/DNA technique was used on dried blood on filter paper spots. From July 1994 to February 2002, mutation analysis was for the DeltaF508 allele. Beginning in March 2002, multimutation analysis of 25 CF mutations was performed. Infants with a positive result on NBS were seen in certified CF centers for sweat testing by means of quantitative pilocarpine iontophoresis, and families received genetic counseling.. From July 1994 to February 2002, there were 120 cases of CF detected by means of NBS (509,794 infants screened), with 53 DeltaF508 homozygotes and 67 compound heterozygotes. There were 8 clinically diagnosed cases of CF (no DeltaF508 allele). The CF incidence was 1:3983 (95%CI, 1:3373-1:4774). From March 2002 to June 2003, multimutation analysis identified 21 cases of classic CF (90,142 infants screened). Sweat tests were successfully performed in infants younger than 1 month.. Early diagnosis of CF through NBS was successfully performed, with an estimated sensitivity rate of 99% using the IRT/25 CFTR multimutation assay.

Topics: Age Factors; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Early Diagnosis; Electrophoresis, Polyacrylamide Gel; Fluoroimmunoassay; Heterozygote; Homozygote; Humans; Incidence; Infant; Infant, Newborn; Iontophoresis; Muscarinic Agonists; Neonatal Screening; Pilocarpine; Polymerase Chain Reaction; Randomized Controlled Trials as Topic; Sensitivity and Specificity; Sweat; Trypsinogen; Wisconsin

To quantitate the proportion of infants identified through cystic fibrosis (CF) newborn screening (NBS) by an immunoreactive trypsinogen (IRT)/DNA screening algorithm who have an unclear diagnosis as defined by the findings of an elevated IRT level and either 1) 2 CF gene (CFTR) mutations detected and sweat chloride level <60 mEq/L; or 2) 0 or 1 CFTR mutations and a "borderline" sweat chloride level >or=30 and <60 mEq/L.. Using the 4-year cohort of CF-affected infants recently described by the Massachusetts CF NBS program, we identified and described the number of infants with the diagnostic characteristics (diagnostic dilemmas) aforementioned.. Of infants with positive results on CF NBS who had 1 CFTR mutation detected and a borderline sweat chloride concentration, nearly 20% displayed a second CFTR mutation on further evaluation. Of all infants with positive CF NBS results considered affected with CF, 11% had a diagnosis that fell into 1 of the diagnostic dilemma categories aforementioned.. Four problematic diagnostic categories generated by CF NBS are defined. In the absence of data on the natural history of such infants, careful follow-up is recommended for infants in whom a definitive diagnosis is elusive.

Topics: Algorithms; Chlorides; Clinical Protocols; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Decision Trees; DNA Mutational Analysis; False Negative Reactions; False Positive Reactions; Follow-Up Studies; Humans; Immunoassay; Infant, Newborn; Massachusetts; Mutation; Neonatal Screening; Practice Guidelines as Topic; Sweat; Trypsinogen

To examine immunoreactive trypsinogen (IRT)-based screening for cystic fibrosis (CF) for recall rate, genotype distribution, and "borderline" sweat test results.. CF newborn screening in Colorado began in 1982, and >1,153,000 infants were screened through 2002 with an IRT-based screen (IRT/IRT).. We have identified 313 infants with CF, giving an overall incidence of 1 in 3684 and a Hispanic incidence of 1 in 6495. Fifty-five infants with meconium ileus (17.6%) were excluded from analysis. Fourteen infants with false-negative results were identified (5.4%). The average recall rate was 0.6%, with a positive predictive value of 4.7%. Ninety-three percent of the infants had at least 1 DeltaF508 mutation, and 98% of the infants had at least 1 mutation from the American College of Medical Genetics recommended panel. Six infants had hypertrypsinogenemia and borderline results on sweat tests (30-60 mmol/L). Increased variability in sweat chloride levels were seen in these infants compared with infants with homozygous DeltaF508. Three children with initial borderline results on sweat tests had CF diagnosed.. The recall and false-negative rates of our IRT/IRT CF screening program are reported. Additionally, genotypes of the patients identified mirror the CF population genotypes, reflecting similar disease severity in the screened population. Finally, infants with persistent hypertrypsinogenemia and borderline sweat test results need long-term follow-up.

Topics: Chlorides; Colorado; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; False Negative Reactions; Fluoroimmunoassay; Genotype; Humans; Incidence; Infant, Newborn; Mandatory Testing; Mutation; Neonatal Screening; Predictive Value of Tests; Radioimmunoassay; Sensitivity and Specificity; Severity of Illness Index; Sweat; Trypsinogen

Since 1979, newborn screening for cystic fibrosis (CF) has been possible by measuring immunoreactive tryspinogen (IRT) in blood spots. In France, a programme based on a three-stage strategy (IRT/DNA/IRT) started in 2002. In the Rhône-Alpes area, the positive screening rate (i.e. the proportion of samples sent for genotyping) observed after the first IRT measurement was higher than the expected rate (0.65% versus 0.50%), without a greater CF incidence. We hypothesized that the IRT reference range could differ according to the ethnic origin of the newborns. 35 141 newborns were studied and divided into two groups: European ethnic group 26 324 (75%) and North African ethnic group 8817 (25%). 243 positive newborns were identified: 146 (60%) in the European ethnic group and 97 (40%) in the North African ethnic group. Three CF patients and 11 unaffected heterozygotes were found in the European group, but no mutations were found in the North African group. Mean IRT values and the percentage of IRT values over the cut-off were significantly higher in the North African group than in the European group (mean IRT = 21.17 microg/L and 19.74 microg/L, p < 0.0001; %IRT > cut-off = 1.1% and 0.5%, respectively). For the positive screened newborns, term and IRT mean were comparable, whereas birth weight was higher in the North African ethnic group. These results lead us to conclude that (i) newborns from families of North African origin have higher IRT values and (ii) most of the positive screened newborns in this population could be considered as 'false positives'. These conclusions could explain, in part, the large variations seen in the positive screening rate in the French CF neonatal screening and raise the question whether it is relevant to adapt cut-off to ethnic origin of the newborns.

Topics: Africa, Northern; Cystic Fibrosis; Ethnicity; Europe; False Positive Reactions; Genetic Carrier Screening; Genetic Testing; Genotype; Heterozygote; Humans; Infant, Newborn; Mass Screening; Models, Statistical; Neonatal Screening; Trypsinogen; White People

Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (DeltaF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing).. We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at approximately 2 days of age was studied.. A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely "genetic diagnosis" was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with DeltaF508 alone. Increased sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with DeltaF508 alone.. Use of multiple-CFTR-mutation testing improved sensitivity and postscreening prediction of CF at the cost of increased referrals and carrier identification.

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Feasibility Studies; Female; Genetic Carrier Screening; Genetic Testing; Humans; Infant, Newborn; Male; Mutation; Neonatal Screening; Sensitivity and Specificity; Trypsinogen

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Humans; Infant, Newborn; Mutation; Neonatal Screening; Trypsinogen

Topics: Cystic Fibrosis; DNA Mutational Analysis; Humans; Infant, Newborn; Neonatal Screening; State Government; Trypsinogen; United States

Though hereditary pancreatitis is a very rare form of pancreatitis, the discovery of the gene for hereditary pancreatitis provides important implications for pancreatitis in general. A premature activation of trypsinogen is likely to occur not infrequently in our daily life as the onset of the disease is well advanced before a drinking habit starts. It probably goes unnoticed in normal individuals because normal inhibitory mechanisms described above prevent the development of pancreatitis. Any disorders or agents that cause abnormalities in this natural protective mechanism can cause pancreatitis. Genotype-phenotype analyses of CFTR mutations in chronic pancreatitis are necessary to establish the relationship between CFTR and this disease. It remains to be shown how a reduction of functional CFTR causes chronic pancreatitis.

Topics: Acute Disease; Chronic Disease; Cystic Fibrosis; Humans; Pancreatitis; Trypsinogen

To compare the cost of diagnosing cystic fibrosis (CF) through a newborn screening program with the traditional method and to estimate the cost of CF diagnosis if a national newborn screening program is implemented.. Surveys were conducted to determine the annual number of sweat tests in 1991 and in 2000 after implementation of statewide screening. A national survey of sweat test costs was used to estimate the annual expense for diagnosing CF in the United States through newborn screening.. Since the introduction of newborn screening for CF, the numbers of sweat tests ordered annually have decreased from 1670 to 804 (including 134 follow-up tests from screening). The current estimated annual cost of Wisconsin CF newborn screening and diagnosis is $4.58 per newborn infant. The estimated annual cost per newly diagnosed CF infant using the traditional method is $4.97 per newborn infant. If no additional sweat tests were ordered outside of the newborn screening program, the estimated annual cost of a Wisconsin CF newborn screening and diagnosis is $2.66 per newborn and $2.47 per newborn for a national CF newborn screening program.. A CF newborn screening program provides a potentially cost-saving alternative to the traditional method of diagnosis of CF.

Topics: Chlorides; Cost Savings; Cystic Fibrosis; Health Care Costs; Humans; Infant, Newborn; Monte Carlo Method; Neonatal Screening; Sweat; Trypsinogen; Wisconsin

Mutations in cystic fibrosis transmembrane conductance regulator (CFTR), in cationic trypsinogen (PRSS1) and in serine protease inhibitor Kazal type 1 (SPINK1) genes have been associated with chronic pancreatitis (alcohol related, idiopathic and hereditary). However, the inheritance pattern is still not clear.. Eighty-two unrelated Brazilian patients with chronic pancreatitis (alcohol-related disease in 64, idiopathic disease in 16, and hereditary disease in 2). Two hundred unrelated individuals with an ethnic distribution comparable to the patients were studied as controls.. Detection of mutations in CFTR, PRSS1, and SPINK1 genes.. Mutations in the CFTR gene were found in 8 patients (9.8%) with chronic pancreatitis, 5 of them with idiopathic disease. Interestingly, the only clinical symptom in a male patient in the alcoholic group, who was a compound heterozygote (DeltaF508/R170C) for two CFTR mutations, was pancreatitis without infertility or pulmonary involvement. In the PRSS1 gene, the E79K change in exon 3 was found in one patient (1.2%) with alcohol-related chronic pancreatitis. Four different alterations were identified in the SPINK1 gene.. Mutations in the CFTR gene represent the major cause of idiopathic chronic pancreatitis in Brazilian patients. No mutation was found in the PRSS1 gene among our patients suggesting further genetic heterogeneity for hereditary and idiopathic chronic pancreatitis. Interestingly, the most frequent SPINK1 N34S mutation was not present in patients or controls. Moreover, the -253C allele for the SPINK1 gene was significantly more frequent in patients than controls (P=0.004), suggesting that it might represent a risk factor for the development of pancreatitis in our population.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brazil; Child; Chronic Disease; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Female; Genetic Predisposition to Disease; Genetic Testing; Humans; Male; Middle Aged; Mutation; Pancreatitis; Pancreatitis, Alcoholic; Serine Proteinase Inhibitors; Trypsin; Trypsinogen

To assess the performance of a two tier neonatal screening programme (IRT/DNA/IRT) for cystic fibrosis, based on immunoreactive trypsinogen (IRT) followed by direct cystic fibrosis transmembrane conductance regulator (CFTR) gene analysis (based on a panel of up to 31 mutations) in hypertrypsinaemic newborn infants and to compare it with a previous screening protocol.. The study comprised all the newborn infants in the period 1 October 1998 to 31 December 1999 in the Lombardia region, north western Italy.. The screening strategy consisted of an immunoreactive trypsinogen assay from dried blood spots, a polymerase chain reaction (PCR) followed by an oligonucleotide ligation assay (PCR-OLA), and a sequence code separation.. 104 609 newborn infants were screened. 1457 hypertrypsinaemic infants (1.39%) were analysed with the PCR-OLA assay. 18 newborn homozygotes or compound heterozygotes for CFTR mutations were identified and referred to the cystic fibrosis (CF) centre at a mean age of 3 weeks. 125 infants presenting only one mutation were recalled for a sweat test: a diagnosis of CF was made in 13 infants, and parents of 112 neonates identified as carriers (1:13) received genetic counselling. The remaining 1314 hypertrypsinaemic newborn infants were recalled for IRT retesting and 177 were referred for a sweat test because the second IRT measurement was above the cut off value. Among this group a further two infants were diagnosed with CF (1.1%) leading to a CF prevalence of 1:3170.. This strategy resulted in an early and accurate diagnosis of CF. The IRT/DNA/IRT protocol with an OLA assay was shown to be useful in an Italian population with a genetic heterogeneity, leading to the identification of 94% of infants with CF.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Genetic Carrier Screening; Genetic Heterogeneity; Genotype; Humans; Infant, Newborn; Italy; Neonatal Screening; Pilot Projects; Prevalence; Program Evaluation; Sensitivity and Specificity; Sequence Deletion; Sweat; Trypsinogen

To analyze the efficiency of the method of neonatal screening for cystic fibrosis (CF) used in Castille and Leon (Spain), which is carried out with blood from Guthrie spots.. A total of 36,086 newborns were studied from January 1999 to June 2001. Immunoreactive trypsinogen (IRT) was quantified in all samples and genetic study covering 87.5 % of mutations in the CFTR gene was carried out when IRT levels were > 60 ng/mL. The sweat test was performed in all children in whom at least one mutation was detected.. IRT values of > 60 ng/mL were found in 285 children (0.79 %). Of these, eight children (2.8 %) were diagnosed with CF and a further 11 children (3.9 %) with a negative sweat test were found to have one mutation and were thus classified as healthy carriers. To date, no false negatives have been detected.. The two-stage screening method fulfills the required criteria. Its sensitivity is 98.5 % and the basic model can be used in other regions although genetic screening should be optimized by pilot programs to identify the local spectrum of CFTR mutations.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Humans; Incidence; Infant, Newborn; Neonatal Screening; Point Mutation; Trypsinogen

A monoclonal antibody (MAb) directed against human immunoaffinity purified trypsinogen has been produced by hybridization of myeloma cells with spleen cells of BALB/c immunized mice. Antibodies were screened by ultramicro-enzyme-linked immunosorbent assay (UMELISA). The MAb was purified by affinity chromatography on protein A-sepharose, and MAb had a high affinity for trypsinogen with the affinity constant equal 2.06 x 10(9) L/mol. Specificity was studied by UMELISA using cross-reactant proteins; MAb gave a positive reaction with native trypsinogen-1 but did not react with the same protein after reduction. The antibody seem to be directed against conformational epitope. The MAb obtained was characterized immunologically and used to develop UMELISA for detection Trypsin. This monoclonal assay enabled the detection of 2.8 ng/mL.

Topics: Animals; Antibodies, Monoclonal; Cystic Fibrosis; Enzyme-Linked Immunosorbent Assay; Humans; Infant, Newborn; Mice; Mice, Inbred BALB C; Neonatal Screening; Trypsin; Trypsinogen

Persistent hypertrypsinaemia in newborn screening for cystic fibrosis (CF) recognises subjects at high risk to be affected. Diagnosis is confirmed by a positive sweat test and/or by the presence of two mutations in the cystic fibrosis transmembrane regulator gene. The aim of the present study was to evaluate the occurrence of a negative sweat test (chloride < 60 mmol/l) during the first months of life, in hypertrypsinaemic infants, which would lead to a delayed diagnosis. We reviewed clinical charts of CF patients born between January 1993 and September 1998, when the neonatal screening programme consisted of an immunoreactive trypsinogen (IRT)/DNA (F508del) + IRT strategy. Laboratory and clinical data were collected for patients diagnosed after 12 months of life. Out of 446,492 newborns, 104 CF patients were diagnosed giving an overall incidence of 1:4293. Of these, six had a blood IRT level above the cut off value (99th percentile) and a negative sweat test in the first trimester of life. At a mean age of 3.5years, the patients were again referred to our CF Centre for re-evaluation in order to confirm or exclude the disorder. Molecular analysis identified the following genotypes: F508del/A309D, F508del/3849 + 10kbC-->T, F508del/R117H (in two patients), R117H/ L997F, and F508del/R117L.. Infants with cystic fibrosis bearing a spectrum of mild cystic fibrosis transmembrane regulator gene mutations may present as hypertrypsinaemic newborns with a sweat chloride within the normal range. Reference values for normal sweat test during the first months of life should be revised. A wide molecular genetic analysis is recommended for newborns presenting persistent hypertrypsinaemia and a sweat test result > 30 mmol/l in order to diagnose atypical forms of the disease.

Topics: Child; Child, Preschool; Chlorides; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Humans; Infant; Infant, Newborn; Male; Mutation; Neonatal Screening; Sweat; Trypsin; Trypsinogen

The increasing evidence of the benefits of neonatal screening for cystic fibrosis (CF) indicates that this procedure could soon be implemented throughout France. The screening strategy currently used involves the detection of infants with elevated levels of immunoreactive trypsinogen (IRT) (approximately 1% of the population), followed by the detection of CFTR gene mutations. However, genetic analysis has certain drawbacks, the most important of which being the management of heterozygotes, and in France the requirement by law of previous informed consent. In cases of CF, pancreatic alterations are already present in utero. A previous study has demonstrated the value of pancreatitis-associated protein (PAP) as a screening test for CF, and has indicated that a feasible two-stage strategy could involve the following: 1) selection of infants with elevated PAP levels; 2) in this group of infants, subsequent detection of those with elevated IRT levels for direct CF diagnosis by the sweat test thereby avoiding the use of genetic analysis. The study aim was to evaluate this strategy in a large number of neonates.. The aforementioned strategy was evaluated in a prospective study involving 47,213 infants in the Provence region of France. In infants with a PAP > 7.5 ng/mL (1.28%), 176 had an elevated IRT level > 700 ng/mL (0.37%). In this limited population sample (0.37% of the total), the sweat test diagnosed five cases of CF. A sixth case involving the monozygous twin of an infant with diagnosed CF remained undetected, probably because of a registration error. Genetic analysis confirmed the diagnosis, and also detected another case in an infant with two CFTR mutations but with a normal phenotype at 20 months of age. As the observed incidence was similar to that which had previously been reported, and as no further case was subsequently detected two years after the end of the study, this indicated that the sensitivity of this screening strategy was satisfactory. Its specificity makes the direct diagnosis of CF cases by the sweat test feasible, without further selection by genetic analysis.. The PAP/IRT technique for CF detection seems to be suitable for mass screening, without the drawbacks of genetic testing.

Topics: Acute-Phase Proteins; Antigens, Neoplasm; Biomarkers, Tumor; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Enzyme-Linked Immunosorbent Assay; Feasibility Studies; France; Genetic Testing; Humans; Infant, Newborn; Lectins, C-Type; Mutation; Neonatal Screening; Pancreatitis-Associated Proteins; Patient Selection; Program Evaluation; Prospective Studies; Sensitivity and Specificity; Trypsinogen

Nonalcoholic chronic pancreatitis is usually idiopathic and often associated with cystic fibrosis gene (CFTR) mutations. It is unknown whether pancreatitis risk correlates with having 1 or 2 CFTR mutations, abnormal epithelial ion transport, or mutations of other genes.. We tested 39 patients with idiopathic chronic pancreatitis (mean age at diagnosis, 33 years) for common mutations of CFTR and of genes encoding a trypsin inhibitor (PSTI) and trypsinogen (PRSS1). To exclude hereditary pancreatitis, we initially relied on family history and subsequently tested for PRSS1 mutations. Twenty subjects were tested for rare CFTR mutations (DNA sequencing) and 11 were tested for extrapancreatic CFTR function (clinical and physiologic evaluation).. Mutations were identified in 24 of 39 subjects. Nine patients had cystic fibrosis-causing mutations, 8 of whom also had mild-variable mutations. Eight others had only mild-variable mutations. Nine subjects had the N34S PSTI mutation and 1 had hereditary pancreatitis (R122H, PRSS1). Pancreatitis risk was increased approximately 40-fold by having 2 CFTR mutations (P < 0.0001), 20-fold by having N34S (P < 0.0001), and 900-fold by having both (P < 0.0001). Subjects with 2 CFTR mutations had abnormal nasal epithelial ion transport and clinical findings suggesting residual CFTR function between that in cystic fibrosis and in carriers. By contrast, subjects with only PSTI mutations had normal CFTR function.. CFTR-related pancreatitis risk correlates with having 2 CFTR mutations and reduced extrapancreatic CFTR function. The N34S PSTI mutation increased risk separately. Testing for pancreatitis-associated CFTR and PSTI genotypes may be useful in nonalcoholic pancreatitis.

Topics: Adolescent; Adult; Alleles; alpha-Amylases; Child; Chlorides; Cystic Fibrosis; Epithelium; Female; Gene Frequency; Genetic Predisposition to Disease; Genotype; Humans; Ion Transport; Male; Middle Aged; Mutation; Pancreatitis; Plant Proteins; Polymorphism, Genetic; Sweat; Trypsin Inhibitors; Trypsinogen

Sweat testing remains the "gold standard" for the diagnosis of cystic fibrosis (CF) and is a critical component of newborn screening programs. We retrospectively reviewed sweat test results reported to a neonatal screening program for CF with respect to completeness of reported results and the values recorded for sweat chloride (Cl(-)) and sodium (Na(+)) concentrations and the Cl(-):Na(+) ratio in screened infants. Thirty-nine of 85 DeltaF508 homozygous (DeltaF508/DeltaF508) and 270 of 274 DeltaF508 heterozygous (DeltaF508/-) infants had sweat tests reported to the screening program. Of those, 30 and 213 sweat test reports, respectively, were complete, i.e., sweat weight, sweat chloride, and sodium were reported. Three centers accounted for 37 of 68 (54%) incomplete results, and 4 centers performed 4 or less post-screening sweat tests in the study period. There were 6 DeltaF508 heterozygous infants with sweat Cl(-) concentrations of 40-60 mmol/L and 4 had CF confirmed by additional genotyping (n = 2) or clinical and repeat sweat Cl results (n = 2). Forty-one percent of DeltaF508/-infants with sweat Cl(-) <40 mmol/L had Cl:Na >1. We conclude that the reporting of incomplete sweat tests is common following newborn screening for CF. Infants with sweat Cl(-) levels of 40-60 mmol/L require further investigation and review, but they almost certainly have CF. The Cl(-):Na(+) ratio does not appear useful in establishing a diagnosis of CF in infants.

Topics: Chlorides; Cystic Fibrosis; Diagnosis, Differential; DNA Mutational Analysis; Female; Genetic Testing; Humans; Infant, Newborn; Male; Neonatal Screening; Retrospective Studies; Sensitivity and Specificity; Sodium; Sweat; Trypsinogen

The cystic fibrosis (CF) clinical spectrum has greatly expanded in the past few years, including atypical forms with low sweat chloride concentrations. Two cases are presented which suggest that children detected by neonatal CF screening whose trypsinogen concentrations are still raised by the second month of age could, despite a negative sweat test, be affected by an atypical CF with fully expressed pulmonary involvement.

Topics: Adolescent; Chlorides; Cystic Fibrosis; Humans; Male; Neonatal Screening; Sputum; Sweat; Trypsinogen

To review the effectiveness of statewide newborn screening for cystic fibrosis (CF) in Victoria over the first 10 years of the program (1989-1998).. Population study involving screening of newborns by immunoreactive trypsinogen (IRT) testing on Day 3-5, followed by either repeat IRT testing (1989-1990) or delta F508 mutation analysis (1991-1998).. All babies screened for CF in a newborn screening program in Victoria in 1989-1998.. The diagnosis of CF.. Of 635,157 babies born in Victoria in the 10 years, 191 were diagnosed with CF. A further 30 cases were detected antenatally, giving an incidence of 1/2874 (95% CI, 1/2519-1/3294). CF was detected early in 182 babies (95.3% of affected babies in the screened cohort)--136 by screening, 35 because they had meconium ileus, and 11 because they were siblings of older children with CF. Nine cases of CF were missed by screening. Of these nine babies, four did not have an elevated neonatal IRT level, one had a normal IRT level at repeat testing at 4-6 weeks (1989-1990), three did not have a delta F508 mutation (1991-1998), and one had a false negative sweat test result. Six of the nine missed babies (67%) were diagnosed within four months of birth.. Newborn screening for CF in Victoria has proven effective in detecting most babies with CF in the newborn period. However, a sweat test should be requested when the clinical features suggest the diagnosis of CF, even if the child has been screened.

Topics: Chlorides; Cystic Fibrosis; Humans; Neonatal Screening; Retrospective Studies; Sweat; Trypsinogen; Victoria

Newborn screening for cystic fibrosis (CF) with immunoreactive trypsinogen (IRT) and DeltaF508 analysis followed by sweat testing misses some infants with CF and detects more DeltaF508 carriers than expected. Some of the apparent DeltaF508 carriers may be DeltaF508 compound heterozygotes with normal sweat electrolyte levels.. Infants identified by newborn screening with an elevated IRT level, one DeltaF508 allele, and a sweat chloride level <60 mmol/L underwent CF mutation analysis, pancreatic stimulation testing, and repeat IRT analysis followed by clinical review and repeat sweat test at 12 months.. Over a 24-month period we identified 122 DeltaF508 heterozygotes and recruited 57; 4 had borderline sweat chloride levels (40 to 60 mmol/L), 5 (8.8%, 95% CI 1.4, 16.2) had a second CF mutation (R117H), and 11 (20%, 95% CI 10, 30) had the intron 8 5T allele. Three had clinical CF at 12 months (initial sweat chloride levels: 53, 51, and 32 mmol/L). Pancreatic electrolyte secretion in the subjects with a borderline sweat chloride level was similar to that in patients with known CF.. The excess of DeltaF508 heterozygotes detected by IRT/DNA screening is associated with the presence of a second mutation or the 5T allele in some infants. Screened infants with borderline sweat chloride levels almost certainly have CF, but long-term follow-up of the infants with the genotype DeltaF508/R117H and DeltaF508/5T is required to determine their outcome. In the meantime, newborn screening should be confined to severe mutations associated with classic CF.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Female; Genetic Carrier Screening; Genotype; Humans; Infant, Newborn; Male; Neonatal Screening; Pancreatic Function Tests; Trypsinogen; Water-Electrolyte Balance

Cationic trypsinogen and cystic fibrosis mutations have been identified in pancreatitis patients, although no study has looked for mutations in both genes in the same patient. Pancreatitis can be induced by alcohol, although not all alcoholics develop pancreatitis. We hypothesize that this phenomenon is due to a genetic predisposition in persons with alcohol-related pancreatitis. We performed sequence analysis of the cationic trypsinogen-coding region in 46 alcohol-related pancreatitis patients and 16 patients with pancreatitis due to causes other than alcohol. We also screened for 40 cystic fibrosis mutations including the 5T allele. No cationic trypsinogen mutations were identified. Cystic fibrosis mutation screening identified the DeltaF508 mutation in two Caucasian alcoholic patients (P<0.025). The cystic fibrosis mutation carrier frequency in African-American alcoholic patients was 3%, which was not significantly increased compared with the normal carrier frequency. The frequency of the 5T allele was not significantly increased compared with the normal population carrier frequency in either racial group. These results may suggest a role for the cystic fibrosis gene in alcohol-related pancreatitis but indicate that cationic trypsinogen mutations are not a common predisposing risk factor for alcohol-related pancreatitis. A multicenter study is necessary to attain sufficient numbers to come to a conclusion.

Topics: Adult; Aged; Alcohol-Related Disorders; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Female; Genetic Counseling; Genetic Predisposition to Disease; Humans; Male; Middle Aged; Pancreatitis; Risk Factors; Trypsin; Trypsinogen

Topics: Cystic Fibrosis; Genetic Testing; Humans; Mutation; Trypsinogen

The biological function of the Reg protein, a non-enzymic protein produced in fairly large amounts by pancreatic acinar cells, remains elusive. Its susceptibility to proteolysis leading to precipitation of the proteolysis product at neutral pH suggests that it could contribute to the protein plugging observed in cystic fibrosis (CF).. To study its behaviour in the serum of CF patients with or without pancreatic insufficiency and to compare it with that of other pancreatic secretory proteins.. 170 patients (93 with CF, 55 controls, and 22 with chronic pancreatitis) were studied.. Reg protein was measured using a specific enzyme immunoassay and its molecular form in CF sera was characterised by gel filtration. Molecular gene expression was investigated by dot-blot hybridisation.. Reg protein was present in all CF sera studied from patients with or without pancreatic insufficiency, and in all cases the level was significantly higher than in controls. Its chromatographic behaviour in CF sera was identical with that of the protein present in normal serum. No correlation was found between the levels of Reg protein and trypsin(ogen) (or lipase) in CF, nor in control sera or normal pancreatic juice. Molecular gene expression of the corresponding proteins investigated in pancreatic tissues showed an absence of correlation between the mRNA levels.. Reg protein may not be a secretory exocrine protein like the digestive enzymes but rather a hormone-like secretory substance with an endocrine or paracrine function.

Topics: Adolescent; Adult; Calcium-Binding Proteins; Child; Child, Preschool; Chromatography, Gel; Chymotrypsinogen; Cystic Fibrosis; Exocrine Pancreatic Insufficiency; Gene Expression; Humans; Immunoenzyme Techniques; Infant; Infant, Newborn; Lipase; Lithostathine; Nerve Tissue Proteins; Pancreatic Juice; Phosphoproteins; RNA, Messenger; Trypsinogen

Newborns with cystic fibrosis (CF) have increased blood immunoreactive trypsinogen concentrations. When screening for CF in the newborn by immunoreactive trypsinogen measurement, an abnormally high proportion of healthy deltaF508 carriers is found among false-positive neonates, suggesting that a relationship could exist between immunoreactive trypsinogen concentration at birth and the genetic status. Therefore, this study analysed the possible relationships between neonatal blood immunoreactive trypsinogen concentrations and genotype in 1842 healthy newborns and 111 CF patients detected by a neonatal screening programme. A close correlation was found between immunoreactive trypsinogen and deltaF508: the probability of a healthy newborn being a carrier of this mutation increased regularly with the neonatal immunoreactive trypsinogen concentration. In CF patients, there was a significant difference between deltaF508 homozygotes and deltaF508/X (X = other mutation) compound heterozygotes with respect to the mean neonatal blood immunoreactive trypsinogen concentration. CF neonates with two mutations affecting the nucleotide binding domains of the cystic fibrosis transmembrane conductance regulator protein had significantly higher mean immunoreactive trypsinogen concentrations than patients with one mutation affecting a membrane-spanning domain. The data strongly suggest that the neonatal immunoreactive trypsinogen concentration is, in part, genetically determined, with a wide range of variations, similar to the features which have been shown for the relations between the genotype and clinical phenotypes of CF patients.

Topics: Case-Control Studies; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Gene Frequency; Genetic Carrier Screening; Genetic Variation; Genotype; Heterozygote; Homozygote; Humans; Mutation; Neonatal Screening; Phenotype; Polymerase Chain Reaction; Trypsinogen

To determine whether pancreatitis associated protein (PAP) is a marker for cystic fibrosis which could be used in neonatal screening for the disease.. PAP was assayed on screening cards from 202,807 neonates. Babies with PAP > or = 15 ng/ml, or > or = 11.5 ng/ml and immunoreactive trypsinogen (IRT) > or = 700 ng/ml were recalled for clinical examination, sweat testing, and cystic fibrosis transmembrane regulator (CFTR) gene analysis.. Median PAP value was 2.8 ng/ml. Forty four cases of cystic fibrosis were recorded. Recalled neonates (n = 398) included only 11 carriers. A receiver operating characteristic curve analysis showed that PAP above 8.0 ng/ml would select 0.76% of babies, including all those with cystic fibrosis, except for one with meconium ileus and two with mild CFTR mutations. Screening 27,146 babies with both PAP and IRT showed that only 0.12% had PAP > 8.0 ng/ml and IRT > 700 ng/ml, including all cases of cystic fibrosis.. PAP is increased in most neonates with cystic fibrosis and could be used for CF screening. Its combination with IRT looks promising.

Topics: Acute-Phase Proteins; Antigens, Neoplasm; Biomarkers; Biomarkers, Tumor; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Humans; Infant, Newborn; Lectins, C-Type; Neonatal Screening; Pancreatitis-Associated Proteins; Predictive Value of Tests; Prospective Studies; Trypsinogen

Cystic fibrosis is a common disease of the Caucasian population and is associated with significant early mortality. We present a simple and rapid method for cystic fibrosis genotyping from filter paper blood spots, using a currently available commercial genotyping kit. Using multiplex technology, genotype information on the four most common UK mutations can easily be obtained within a single working day. Used in conjunction with current immunoreactive typsinogen screening protocols, blood spot genotyping offers a method of hastening the diagnosis, and thus treatment, of cystic fibrosis.

Topics: Child; Child, Preschool; Cystic Fibrosis; Diagnostic Techniques and Procedures; DNA; Genotype; Humans; Mutation; Sensitivity and Specificity; Trypsinogen

To evaluate neonatal screening for cystic fibrosis (CF), including study of the screening procedures and characteristics of false-positive infants, over the past 10 years in Wisconsin. An important objective evolving from the original design has been to compare use of a single-tier immunoreactive trypsinogen (IRT) screening method with that of a two-tier method using IRT and analyses of samples for the most common cystic fibrosis transmembrane regulator (CFTR) (DeltaF508) mutation. We also examined the benefit of including up to 10 additional CFTR mutations in the screening protocol.. From 1985 to 1994, using either the IRT or IRT/DNA protocol, 220 862 and 104 308 neonates, respectively, were screened for CF. For the IRT protocol, neonates with an IRT >/=180 ng/mL were considered positive, and the standard sweat chloride test was administered to determine CF status. For the IRT/DNA protocol, samples from the original dried-blood specimen on the Guthrie card of neonates with an IRT >/=110 ng/mL were tested for the presence of the DeltaF508 CFTR allele, and if the DNA test revealed one or two DeltaF508 alleles, a sweat test was obtained.. Both screening procedures had very high specificity. The sensitivity tended to be higher with the IRT/DNA protocol, but the differences were not statistically significant. The positive predictive value of the IRT/DNA screening protocol was 15.2% compared with 6.4% if the same samples had been screened by the IRT method. Assessment of the false-positive IRT/DNA population revealed that the two-tier method eliminates the disproportionate number of infants with low Apgar scores and also the high prevalence of African-Americans identified previously in our study of newborns with high IRT levels. We found that 55% of DNA-positive CF infants were homozygous for DeltaF508 and 40% had one DeltaF508 allele. Adding analyses for 10 more CFTR mutations has only a small effect on the sensitivity but is likely to add significantly to the cost of screening.. Advantages of the IRT/DNA protocol over IRT analysis include improved positive predictive value, reduction of false-positive infants, and more rapid diagnosis with elimination of recall specimens.

Topics: Apgar Score; Clinical Laboratory Techniques; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA; Humans; Infant, Newborn; Mass Screening; Mutation; Predictive Value of Tests; Radioimmunoassay; Sensitivity and Specificity; Trypsinogen; Wisconsin

Cystic fibrosis (CF) is a genetic disease that can be detected in newborn infants (i.e., those aged < or = 1 month) by immunotrypsinogen testing. The sensitivity and specificity of such testing can now be improved as a result of the recent discovery of the Cystic Fibrosis Transmembrane Conductance Regulatory (CFTR) gene. Although limited CF screening for newborns has been used since the 1980s, the clinical, social, and economic outcomes of population-based screening are controversial. During January 1997, a workshop was convened at CDC in Atlanta, Georgia to discuss the benefits and risks associated with screening newborns for CF and to develop public health policy concerning such screening. The workshop planning committee comprised representatives from CDC, the Cystic Fibrosis Foundation, the National Institutes of Health, and the University of Wisconsin. Experts in the fields of CF, public health, the screening of newborns, and economics also contributed to discussions. Workshop participants addressed a) benefits and risks, b) laboratory testing, and c) economics concerning the implementation of routine CF screening for newborns. Summaries of these discussions and the resulting workshop recommendations are presented in this report. These recommendations, developed by workshop participants, will be useful to medical and public health professionals and state policymakers who are evaluating the merits of population-based screening of newborns for CF.

Topics: Clinical Laboratory Techniques; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Carrier Screening; Genetic Testing; Health Policy; Humans; Infant, Newborn; Mass Screening; Policy Making; Risk; Trypsinogen

Plasma immunoreactive cationic trypsin (ogen) is elevated in cystic fibrosis during early infancy, before exocrine pancreatic insufficiency is fully developed. The recently developed cystic fibrosis mouse model carrying a mutated gene presents only minor pathologic findings in the pancreas. However, the reserpinized rat model shows cystic fibrosis-like defects in various exocrine glands, including the exocrine pancreas. Plasma immunoreactive cationic trypsin (ogen) has not been studied yet in this model. The present study explored the plasma immunoreactive cationic trypsin (ogen) pattern and possible mechanisms in this rat model. Plasma immunoreactive cationic trypsin (ogen) (RIA), pancreatic juice volume, protein, and trypsin, and pancreas weight were determined in rats treated with reserpine (0.5 mg/kg/day subcutaneously) for four or seven days, following cerulein stimulation (5 micrograms/kg/dose intraperitoneally), versus pair-fed controls. The first of four consecutive 30 min periods revealed peak values in all parameters. Four-day reserpine-treated rats demonstrated significantly higher plasma immunoreactive cationic trypsin (ogen) levels (167.3 +/- 12.8 vs 88.9 +/- 6.1 ng/ml; P < 0.0001) with similar values of pancreatic juice trypsin (8.2 +/- 2.4 vs 6.6 +/- 1.8 units/mg protein; P = NS) and volume (5.6 +/- 1.3 vs 4.2 +/- 1.6 mg/min/g pancreas; P = NS), compared to controls. Rats treated with reserpine for seven days revealed significantly lower values of plasma immunoreactive cationic trypsin (ogen) (39.2 +/- 8.4 vs 66.8 +/- 4.9 ng/ml; P < 0.001), pancreatic juice trypsin (1.9 +/- 0.3 vs 3.2 +/- 0.9 units/mg protein; P < 0.001) and volume (1.6 +/- 0.7 vs 3.1 +/- 0.6 mg/min/g pancreas; P < 0.001) compared to controls. We conclude that the reserpinized rat model resembles human cystic fibrosis as to elevated plasma immunoreactive cationic trypsin (ogen) before exocrine pancreatic insufficiency is fully developed. Since exocrine pancreatic volume secretion is intact at this stage, the mechanism of elevated plasma immunoreactive cationic trypsin is probably not due to ductular obstruction. We suggest that this model be studied further in order to investigate other possible mechanisms.

Topics: Analysis of Variance; Animals; Cystic Fibrosis; Disease Models, Animal; Humans; Male; Mice; Pancreatic Juice; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Reserpine; Time Factors; Trypsin; Trypsinogen

To determine whether an adequate volume of sweat could be obtained routinely from infants younger than 6 weeks old and to evaluate sweat chloride levels in infants with known genotype statuses, including heterozygote carriers for cystic fibrosis (CF).. Infants were evaluated using pilocarpine iontophoresis and measurement of sweat volume and chloride concentration. The majority of these infants were referred because of newborn screening test results positive for CF based on immunoreactive trypsinogen analysis. DNA analyses for the 3-base pair deletion at codon 508 of the CF transmembrane regulator gene (F508 mutation) were performed whenever possible, and patients with CF were categorized by genotype.. Sweat tests were performed successfully (>/-50 mg of sweat) in 99.3% of the infants tested, and there was no difference in the proportion of unsuccessful tests in infants younger than or older than 6 weeks of age. The normal mean +/- SD sweat chloride was 10.6 +/- 5.2 mEq/L (95% confidence interval, 9.9-11.3). Patients with CF who are F508 homozygotes or F508 compound heterozygotes or who have two other non-F508 mutant alleles were shown to have similar sweat chloride levels, with mean values of 99.9, 98.8, and 96.6 mEq/L, respectively. The group of infants who were found to be CF (F508) heterozygote carriers, when compared with the healthy group, had mildly but significantly increased sweat chloride concentrations, with a mean +/- SD of 14.9 +/- 8.4 mEq/L (95% confidence interval, 13.4-16.4).. Quantitative pilocarpine iontophoresis can be used successfully in infants younger than 6 weeks of age who are undergoing routine diagnostic evaluations to follow up newborn screening test results that are positive for CF. The upper limit of normal sweat chloride in infants should be revised to 40 mEq/L (mean + 3 SD of the CF heterozygote carrier group). CF heterozygote carrier infants with one F508 mutant allele show phenotypic manifestations of CF, including subclinical elevations of sweat chloride.

Topics: Age Factors; Alleles; Base Composition; Chlorides; Codon; Cystic Fibrosis; DNA; Follow-Up Studies; Gene Deletion; Genes, Regulator; Genotype; Heterozygote; Homozygote; Humans; Infant; Infant, Newborn; Iontophoresis; Mutation; Neonatal Screening; Parasympathomimetics; Pilocarpine; Sweat; Trypsinogen

Newborn screening for cystic fibrosis (CF) by examining the levels of immunoreactive trypsinogen was introduced in Victoria in 1989. This was modified by the addition of testing for the common CF gene mutation, delta F508, in 1990. Problems with the first newborn screening protocol were overcome with the addition of the DNA test as there was no need to contact the majority of families, there was a reduced number of sweat tests, and less anxiety was experienced by parents. The mode of diagnosis changed from failure to thrive, steatorrhoea, rectal prolapse, and family history to diagnosis through newborn screening. Newborn screening dramatically reduced the time of diagnosis of CF to approximately six weeks or less in the majority of cases. Since the introduction of newborn screening, the uptake of prenatal diagnosis in CF families has increased two and a quarter fold.

Topics: Algorithms; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA Mutational Analysis; Genetic Testing; Humans; Infant, Newborn; Neonatal Screening; Polymerase Chain Reaction; Sequence Deletion; Time Factors; Trypsinogen; Victoria

We studied serial measurements of serum cationic trypsinogen in patients with cystic fibrosis to assess the predictability of changes in individuals and the value of longitudinal measurement in defining pancreatic status. Three hundred twenty-nine patients with cystic fibrosis, aged 3 days to 40 years, had serum levels of trypsinogen measured on 2 to 12 occasions for periods ranging from 1 week to 7 years. Patients were classified into three groups on the basis of 72-hour fecal fat studies performed at the time of diagnosis. Two hundred thirty-three patients had pancreatic insufficiency (PI), 78 had pancreatic sufficiency (PS), and 18 had PS at diagnosis but acquired PI during follow-up (PS-->PI). Infants with PI had greatly elevated serum trypsinogen levels that fell sharply in the first years of life, so that by age 7 years more than 95% had subnormal values; individual patient values followed a predictable course similar to previously reported cross-sectional age-related values. In patients with PS, serum trypsinogen levels generally remained within or above the normal range and, after age 10 years, were well above the upper limit for PI patients. Within-patient variance was significantly greater (p < 0.0001) in patients with PS than in those with PI who were older than 7 years of age. Changes in patients within PS-->PI generally followed the pattern seen in patients with PI, but values in older patients tended to be in the higher range. We concluded that serial measurement of serum trypsinogen is a valuable tool for monitoring the pancreatic status of patients with cystic fibrosis and PS.

Topics: Adolescent; Adult; Aging; Child; Child, Preschool; Cystic Fibrosis; Disease Progression; Exocrine Pancreatic Insufficiency; Feces; Female; Humans; Infant; Infant, Newborn; Lipids; Longitudinal Studies; Male; Pancreatic Function Tests; Prognosis; Trypsinogen

We have evaluated a two-tier neonatal cystic fibrosis (CF) screening of immunoreactive trypsinogen (IRT) followed by CFTR gene mutation analysis using a systematic scanning of exons 7, 10, and 11, and, if necessary, by direct DNA sequencing. Over an 18-month period we screened 32,300 neonates born in the western part of Britanny. The first tier, involving IRT screening at 3 days of age, utilizes a low elevation of the trypsinogen level (600 ng/ml), which is highly sensitive. The second tier, which corresponds to the exhaustive screening for mutations in three exons of the gene, is highly specific for this population (Britanny). The false positive rate is very low, and no false negatives have been reported to date. This strategy has allowed the identification of five novel alleles (V322A, V317A, 1806 del A, R553G, G544S).

Topics: Base Sequence; Cystic Fibrosis; DNA Mutational Analysis; France; Genetic Counseling; Humans; Incidence; Infant, Newborn; Molecular Sequence Data; Mutation; Neonatal Screening; Pilot Projects; Trypsinogen

We aimed to discover whether neonatal infection affected levels of the immunoreactive trypsin (IRT) assay, which is used as a screening test for cystic fibrosis. Forty babies who had clinical features suggesting infection had blood spot specimens for IRT taken at the same time as blood for culture. Of 27 babies believed clinically to have infection, 19 had positive blood cultures and eight had negative culture. In retrospect, 13 were not thought to have infection. The mean (SD) IRT results in these three groups were 15 (8), 11 (4), and 16 (6) micrograms/L, respectively. The mean (SD; range) IRT result for all 40 babies was 14 (7; 10-39). Not only did no babies have elevated IRT results at routine neonatal screening, but none have presented with clinical features suggestive of cystic fibrosis since hospital discharge. Neonatal infection does not appear to cause elevated IRT levels and should therefore not cause false-positive results in mass neonatal screening.

Topics: C-Reactive Protein; Cystic Fibrosis; False Positive Reactions; Female; Humans; Infant, Newborn; Infections; Male; Neonatal Screening; Prospective Studies; Trypsinogen

Infants born in Wisconsin are being screened for cystic fibrosis (CF) associated with the F508 mutation. This screening program has been developed during 9 years of research supported by the National Institutes of Health and involves a unique, two-tier system employing measurement of immunoreactive trypsinogen (IRT) initially. When the IRT level is high, DNA is extracted from the neonatal dried blood specimen and analyzed for the F508 mutant allele, following polymerase chain reaction (PCR) amplification; the F508 mutation is present in more than 90% of CF patients and accounts for the common, severe form of the disease. Infants with a positive DNA test are either CF heterozygote carriers or CF patients, depending on the results of a sweat test, which should be performed at 4 weeks of age. Screening the newborn population for CF provides the opportunity for early nutritional and respiratory interventions, as well as genetic counseling. This represents the first population-based application of molecular genetics for detection of a major congenital disorder causing serious public health problems. The process by which the recommendation was reached to screen for CF is described in this article, along with new information on the pathogenesis of CF, its clinical presentation, the rationale for newborn screening, and the method developed for the screening program.

Topics: Cystic Fibrosis; DNA Mutational Analysis; Humans; Infant, Newborn; Mass Screening; Trypsinogen; Wisconsin

To assess the performance and impact of a two tier neonatal screening programme for cystic fibrosis based on an initial estimation of immunoreactive trypsinogen followed by direct gene analysis.. Four year prospective study of two tier screening strategy. First tier: immunoreactive trypsinogen measured in dried blood spot samples from neonates aged 3-5 days. Second tier: direct gene analysis of cystic fibrosis mutations (delta F508, delta I506, G551D, G542X, and R553X) in samples with immunoreactive trypsinogen concentrations in highest 1% and in all neonates with meconium ileus or family history of cystic fibrosis.. South Australian Neonatal Screening Programme, Adelaide.. All 88,752 neonates born in South Australia between December 1989 and December 1993.. Neonates with two identifiable mutations were referred directly for clinical assessment and confirmatory sweat test; infants with only one identifiable mutation were recalled for sweat test at age 3-4 weeks. Parents of neonates identified as carriers of cystic fibrosis mutation were counselled and offered genetic testing.. Identification of all children with cystic fibrosis in the screened population.. Of 1004 (1.13%) neonates with immunoreactive trypsinogen > or = 99th centile, 912 (90.8%) had no identifiable mutation. 23 neonates were homozygotes or compound heterozygotes; 69 carried one identifiable mutation, of whom six had positive sweat tests. Median age at clinical assessment for the 29 neonates with cystic fibrosis was 3 weeks; six had meconium ileus and two had affected siblings. 63 neonates were identified as carriers of a cystic fibrosis mutation. Extra laboratory costs for measuring immunoreactive trypsinogen and direct gene analysis were $A1.50 per neonate screened.. This strategy results in early and accurate diagnosis of cystic fibrosis and performs better than screening strategies based on immunoreactive trypsinogen measurement alone.

Topics: Cystic Fibrosis; DNA Mutational Analysis; Genes; Genetic Counseling; Genetic Techniques; Genetic Testing; Humans; Incidence; Infant, Newborn; Mutation; Neonatal Screening; Predictive Value of Tests; Prospective Studies; South Australia; Trypsinogen

We compared pancreatic acinar and ductal secretion in two patients with Johanson-Blizzard syndrome, age-matched control subjects, and patients with other primary pancreatic diseases. Patients with Johanson-Blizzard syndrome had preservation of ductular output of fluid and electrolytes, as in patients with Shwachman syndrome but differing from those with cystic fibrosis, who have a primary ductular defect. They also had decreased acinar secretion of trypsin, colipase and total lipase, and low serum immunoreactive trypsinogen levels, consistent with a primary acinar cell defect.

Topics: Case-Control Studies; Colipases; Consanguinity; Cystic Fibrosis; Exocrine Pancreatic Insufficiency; Female; Humans; Infant; Infant, Newborn; Lipase; Malabsorption Syndromes; Male; Pancreas; Pancreatic Diseases; Pancreatic Ducts; Syndrome; Trypsin; Trypsinogen

Newborn screening for cystic fibrosis (CF) has been carried out on approximately 106,000 neonates in western Pennsylvania since 1987 using the immunoreactive trypsinogen (IRT) assay on dried filter paper blood specimens (DBS). Molecular analysis utilizing a duplicate DBS from the same sample was implemented in November 1989 for newborns having elevated IRT levels. DNA is amplified directly from the DBS and the amplified products are tested for the delta F508 deletion and several common exon 11 mutations. Substituting dUTP for dTTP in the PCR reaction and an initial treatment with uracil N-glycosylase (UNG) virtually eliminates PCR carryover contamination. The number of confirmed cases of CF is 20, giving an estimated incidence of 1:5287 in the western Pennsylvania population. Eight of the CF patients are homozygous and 12 are compound heterozygotes for the delta F508 deletion and a second mutation. Two of the compound heterozygotes carry the G551D mutation and one has the R553X mutation. Twenty-one additional neonates that are heterozygous for the delta F508 mutation are normal carriers for CF. In approximately 55% of the cases, molecular analysis of the CF gene confirmed the diagnosis of CF prior to sweat testing. The incorporation of molecular analysis into our CF screening program increases the specificity of the screening strategy and has the potential to decrease the false positive and sweat test referral rate, reduce parental anxiety, and bring CF infants to the attention of physicians more rapidly.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; DNA; Exons; Gene Deletion; Humans; Infant, Newborn; Membrane Proteins; Mutation; Neonatal Screening; Pennsylvania; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Trypsinogen

A coated microtiter-well, enzyme-linked immunometric assay for quantifying immunoreactive trypsinogen in dried blood spots was modified to use time-resolved fluorescence of europium in place of end-point enzymatic color development as the quantification step. The streptavidin-horseradish peroxidase and color development solutions supplied as packaged reagents were replaced by europium-labeled avidin, and the signal was developed with commercially available enhancement solution and read by time-resolved fluorescence. The change of label from enzyme to europium increased the dynamic range of the assay by about 5-fold, reduced the detection limit 10-fold, and halved the intra- and interassay imprecision. The improved analytical precision and stability of the modified assay resulted in a more precise description of the population distribution of immunoreactive trypsinogen values in newborns, showing less variance in the upper centiles. This effect is of paramount importance when using this assay for neonatal screening for cystic fibrosis.

Topics: Avidin; Cystic Fibrosis; Europium; Fluorescent Dyes; Fluoroimmunoassay; Humans; Immunoenzyme Techniques; Indicators and Reagents; Infant, Newborn; Neonatal Screening; Reference Values; Trypsinogen

To evaluate the feasibility and efficacy of measuring immunoreactive trypsinogen in blood to screen for cystic fibrosis, we performed this test in 279,399 newborns in Colorado from 1982 to 1987.. Immunoreactive trypsinogen was measured in dried blood spots when the infants were 1 to 4 days old; if the level was elevated (greater than or equal to 140 micrograms per liter), the measurement was repeated (mean age, 38 days); if the level was again elevated, sweat testing was performed (mean age, 49 days). For the second test, two cutoff levels (120 and 80 micrograms per liter) were evaluated.. We found an incidence of cystic fibrosis of 1 in 3827 (0.26 per 1000), with 3.2 newborns per 1000 requiring repeat measurement. When adjusted for race and compliance with testing, the incidence among the white infants (1 in 2521) was close to the expected incidence. The false positive rate with the initial cutoff level (92.2 percent) was similar to the rate found in neonatal screening programs for other diseases. False negative results occurred because of laboratory error or changes in procedure (three infants) and trypsinogen concentrations lower than the initial cutoff level (three infants) or lower than the remeasurement cutoff level of 120 micrograms per liter (one infant). Sweat tests were negative in 168 infants with an elevated initial trypsinogen level but a level below 80 micrograms per liter on remeasurement, confirming the value of 80 micrograms per liter as an appropriate cutoff for repeat-test results. Overall, 95.2 percent of the infants with cystic fibrosis (95 percent confidence interval, 85 to 99 percent) who did not have meconium ileus could be identified with the use of a trypsinogen cutoff level of 140 micrograms per liter on initial testing and 80 micrograms per liter on repeat testing.. Statewide screening for cystic fibrosis based on measurements of immunoreactive trypsinogen in dried blood spots is feasible and can be implemented with acceptable rates of repeat testing and false positive and false negative results.

Topics: Clinical Protocols; Cystic Fibrosis; False Negative Reactions; False Positive Reactions; Humans; Incidence; Infant, Newborn; Neonatal Screening; Pilot Projects; Sweat; Trypsinogen

Topics: Colorado; Cystic Fibrosis; False Positive Reactions; Humans; Infant, Newborn; Neonatal Screening; Trypsinogen

Topics: Chromosomes, Human, Pair 13; Cystic Fibrosis; False Positive Reactions; Genetic Testing; Humans; Male; Syndrome; Trisomy; Trypsinogen

To assess the effectiveness of a two tier neonatal screening strategy for cystic fibrosis, which combines estimation of immunoreactive trypsinogen followed by direct gene analysis in dried blood spot samples collected at age 5 days.. Prospective study of two tier screening strategy. The first tier of testing immunoreactive trypsinogen concentration was measured in dried blood spot samples from neonates aged 4-5 days. In the second tier direct gene analysis to detect cystic fibrosis mutations deltaF508 and deltaI506 was performed in those blood spot samples which produced the highest 1% of immunoreactive trypsinogen values. Direct gene analysis was also performed on blood spot samples from infants with suspected or confirmed meconium ileus, regardless of the immunoreactive trypsinogen value.. The South Australian Neonatal Screening Programme, operating from the department of chemical pathology at Adelaide Children's Hospital. Subjects--All 12,056 neonates born in South Australia between December 1989 and June 1990. No selection criteria were applied.. All infants found to have two recognised cystic fibrosis mutations on direct gene analysis were referred directly for clinical management, and those with one recognised cystic fibrosis mutation were recalled for a sweat test; their families were given genetic counselling.. Direct or exclusion of cystic fibrosis by sweat testing of neonates identified as being at high risk of cystic fibrosis on screening and of those at minimum risk but whose subsequent clinical history raised suspicion about the disease.. Of the 12,056 infants screened, 11,907 (98.8%) were reported as "cystic fibrosis not indicated" on the basis of low immunoreactive trypsinogen values. Of the 148 (1.23%) infants with raised immunoreactive trypsinogen values and one (0.008%) with meconium ileus, 132 (1.09%) were reported as cystic fibrosis not indicated, four (0.033%) were identified as having cystic fibrosis, and 13 (0.108%) were recalled for sweat testing after direct gene analysis for the presence of the deltaF508 and deltaI506 cystic fibrosis mutations. No cases of affected infants are known to have been missed to date.. The strategy of measurement of immunoreactive trypsinogen followed by direct gene analysis is a highly specific neonatal screen for cystic fibrosis, requiring only 2.8 families to be contacted for every case of cystic fibrosis diagnosed.

Topics: Cystic Fibrosis; DNA Mutational Analysis; Female; Humans; Infant, Newborn; Male; Mutation; Neonatal Screening; Prospective Studies; South Australia; Trypsinogen

A novel monoclonal antibody based enzyme immunoassay (EIA) method for the measurement of the human cationic trypsinogen (NeoScreen, AGEN Biomedical Ltd., Acacia Ridge, Australia) in dried blood spots for the neonatal screening of cystic fibrosis was evaluated. The calibration standards provided as dried blood spots by AGEN are highly unstable and must be replaced with user prepared materials. Reference values from control individuals were obtained by parametric methods. A preliminary comparison with a polyclonal antibody based RIA method (Trypsik, SORIN Biomedica, Saluggia, Italy) was performed. Regression analysis between the RIA and the EIA methods gave a coefficient of correlation of 0.58 for RIA values less than 40 micrograms/L and of 0.77 for RIA values greater than or equal to 40 micrograms/L. Average CV of the within-run imprecision for the EIA method was 19.6% and for the RIA method 28.8%. CVs of the between-run imprecision at low, intermediate and high values for the EIA method were 23.7%, 15.8%, 15.6% and for the RIA method 20.6%, 14.4%, 11.2%. The diagnostic accuracy analyzed by a Receiver Operating Characteristics (ROC) curve of the RIA method gave a maximum accuracy of 190.9 while that of a simulated ROC curve for the EIA method was 193.0. We found that the precision and the diagnostic accuracy of the EIA method (AGEN) are equal to or better than those of one of the RIA methods.

Topics: Calibration; Cystic Fibrosis; Evaluation Studies as Topic; Humans; Immunoenzyme Techniques; Radioimmunoassay; Reference Values; Regression Analysis; Trypsinogen

Serum immunoreactive trypsin (IRT) concentrations are elevated in newborn children with cystic fibrosis (CF) and subsequently fall, in most cases, to values below normal. To evaluate the molecular form(s) of IRT present in serum, we have performed serum activation by enterokinase and have measured serum IRT before and after activation. This approach is based on the postulate that enterokinase converts trypsinogen into trypsin, and this trypsin would then be mainly trapped by alpha 2-macroglobulin, thus escaping the assay. This assumption was confirmed in the 28 controls studied, where the mean percentage (+/- S.D.) of IRT recovery after serum activation was 13.7 +/- 2.9. Previous inhibition of alpha 2-macroglobulin by methylamine raised the recovery over 85%, confirming that most of the serum IRT present in controls was in the form of trypsinogen. Identical results were obtained in the serum of 10 obligate heterozygotes and in 57 out of 80 CF patients. In 23 CF patients the mean percentage of IRT recovery after serum activation was 41.6 +/- 17.6. Gel-filtration studies were performed on the sera of the CF patients showing an abnormal increase in the IRT recovery after serum activation. We could demonstrate that IRT was distributed in two fractions: one eluted with the Mr 25,000 protein as usually found in controls and other CF sera, and the other eluted with the Mr 75,000 protein corresponding to a complex of trypsin with alpha 1-proteinase inhibitor. These results show that, in these sera, active trypsin has been directly released in blood. These findings suggest that in some patients with CF, subclinical attacks of acute pancreatitis may occur.

Topics: alpha 1-Antitrypsin; alpha-Macroglobulins; Chromatography, Gel; Cystic Fibrosis; Enteropeptidase; Enzyme Activation; Heterozygote; Humans; Molecular Weight; Serine Endopeptidases; Trypsin; Trypsinogen

Blood immunoreactive trypsinogen (IRT) is elevated in newborns with cystic fibrosis (CF) and has been used as a neonatal screening test. However, not only is the benefit of early diagnosis unknown, but also the sensitivity, specificity, and time related decline of IRT values have yet to be comprehensively evaluated. This report describes the characteristics of infants with a false-positive IRT in our experience with CF screening of 87,000 infants. The IRT value was elevated in 92 newborns; 13 had a confirmed diagnosis of CF by quantitative pilocarpine iontophoresis sweat testing, and 79 infants did not have CF and were therefore classified as false positives by IRT screening. In order to test the hypothesis that perinatal stress factors are associated with high neonatal IRT values, we evaluated Apgar scores at 1 and 5 minutes. We found that the scores of false-positive infants were significantly lower (P = 0.0004 and P = 0.0102 at 1 and 5 minutes, respectively), compared with infants in the general population. While perinatal asphyxia as reflected by low Apgar scores is an associated factor accounting for an elevated IRT value, the majority of non-CF newborns with an elevated IRT have normal Apgar scores.

Topics: Apgar Score; Cystic Fibrosis; False Positive Reactions; Humans; Infant, Newborn; Mass Screening; Predictive Value of Tests; Radioimmunoassay; Trypsinogen

Primary care physicians have been very cooperative in referring screened patients to the two designated CF centers in Wisconsin--the University of Wisconsin Cystic Fibrosis Center, and the center at the Medical College of Wisconsin in Milwaukee--and their help has made this study possible. By 1990, we anticipate that meaningful clinical comparisons between the screened and control groups will be possible, and at that time we can begin to obtain some definitive answers concerning the benefits and potential risks of neonatal screening for cystic fibrosis. At this time, it would be premature to make a decision concerning the efficacy of screening for cystic fibrosis for the State of Wisconsin. It is very important that the study go to completion before making conclusive recommendations. We are eager to meticulously document the natural history of CF by following study patients for a long time. Answers to questions concerning rate of decline of the IRT value in true positives, psychosocial risks of screening to true positives, effect on future reproductive plans, and the cost effectiveness of the screening program will not be available for at least two more years. False positive IRT results seem to be related to perinatal asphyxia. We postulate the mechanism is ischemia in the pancreas related to hypoxia during the perinatal period leading to transient release of trypsin from the pancreas into the bloodstream. Decline of the IRT result over time is of great interest because a repeat blood sampling approach would hopefully eliminate several false positives.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Cystic Fibrosis; Humans; Infant, Newborn; Mass Screening; Trypsinogen; Wisconsin

Topics: Child; Child, Preschool; Cystic Fibrosis; Fats; Feces; Female; Humans; Infant; Male; Pancreas; Pancreatic Function Tests; Trypsinogen

A four year regional screening programme to detect cystic fibrosis using measurement of immunoreactive trypsinogen is described. During this period 60 infants were diagnosed; 34 by screening, 12 born with meconium ileus, and 14 not identified by the screening assay but who presented with clinical symptoms at a later age, giving an incidence of cyst fibrosis in the region during this time of 1/1807. Screening has resulted in earlier detection of cystic fibrosis in many infants, thus allowing treatment to be instituted at an early age, and genetic counseling offered to the parents. There were a number of false positives and false negatives with the immunoreactive trypsinogen screening assay. In addition, eight infants who were sweat tested at an early age had a sweat sodium concentration of less than 70 mmol/l, although they were subsequently shown to have cystic fibrosis. These results confirm other published data showing that sweat sodium results may be low in very young infants with cystic fibrosis. At the time of diagnosis seven (20%) of the infants identified by screening were totally asymptomatic and several additional children had symptoms of such a type that the diagnosis of cystic fibrosis had not been considered at the time of screening. Despite the problems experienced it has been decided to continue screening.

Topics: Age Factors; Child; Child, Preschool; Chlorides; Cystic Fibrosis; False Negative Reactions; False Positive Reactions; Family; Humans; Infant; Infant, Newborn; Mass Screening; Northern Ireland; Predictive Value of Tests; Radioimmunoassay; Sodium; Sweat; Time Factors; Trypsinogen

An enzyme immunoassay (EIA) with monoclonal antibodies against human trypsinogen in neonatal blood-spots has been evaluated for screening for neonatal cystic fibrosis (CF). In a retrospective study, 36 of 39 CF samples were distinguished from controls matched for age and storage time. 7 infants with CF were detected in 16,500 infants screened in a prospective study. The EIA is quicker and less labour intensive than conventional assays for the detection of immunoreactive trypsin and may have further advantages of specificity and sensitivity for monitoring the release of pancreatic zymogens in CF.

Topics: Antibodies, Monoclonal; Cystic Fibrosis; Evaluation Studies as Topic; Humans; Immunoenzyme Techniques; Infant, Newborn; Prospective Studies; Retrospective Studies; Trypsinogen

Serum immunoreactive cationic trypsinogen levels were determined in 99 control subjects and 381 cystic fibrosis (CF) patients. To evaluate the status of the exocrine pancreas all CF patients had previously undergone fecal fat balance studies and/or pancreatic stimulation tests. Three hundred fourteen CF patients had fat malabsorption and/or had inadequate pancreatic enzyme secretion (pancreatic insufficiency) requiring oral pancreatic enzyme supplements with meals. Sixty-seven CF patients did not have fat malabsorption and/or had adequate enzyme secretion (pancreatic sufficiency) and were not receiving pancreatic enzyme supplements with meals. Mean serum trypsinogen in 99 control subjects was 31.4 +/- 14.8 micrograms/liter (+/- 2 SD) and levels did not vary with age or sex. In CF infants (less than 2 yr) with pancreatic insufficiency, mean serum trypsinogen was significantly above the non-CF values (p less than 0.001). Ninety-one percent of the CF infants had elevated levels. Serum trypsinogen values in the pancreatic insufficient group declined steeply up to 5 years, reaching subnormal values by age 6. An equation was developed which described these age-related changes very accurately. Only six CF patients with pancreatic insufficiency had serum trypsinogen levels above the 95% confidence limits of this equation. In contrast, there was no age related decline in serum trypsinogen among the CF group with pancreatic sufficiency. Under 7 yr, serum trypsinogen failed to distinguish the two groups. In those over 7 yr of age, however, serum trypsinogen was significantly higher than the CF group with pancreatic insufficiency (p less than 0.001), and 93% had values within or above the control range.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Age Factors; Child; Child, Preschool; Cystic Fibrosis; Exocrine Pancreatic Insufficiency; Female; Humans; Infant; Male; Radioimmunoassay; Sex Factors; Trypsinogen

In patients with CF, serum pancreatic cationic trypsinogen has proven to be useful for newborn diagnostic screening and also as a test of pancreatic function in the older patient. However, an assay for serum anionic trypsinogen is of no value as a test of pancreatic function in CF due to an apparent artifactual elevation of this enzyme in some patients. In this study, we evaluated the extent of the abnormality in the anionic trypsinogen assay and also elucidated the nature of the interfering material. CF patients were grouped according to the presence (pancreatic insufficiency) or absence (pancreatic sufficiency) of steatorrhea. In CF infants, both serum cationic and anionic trypsinogen levels were greatly elevated. Serum cationic trypsinogen declined with age in patients with pancreatic insufficiency, reaching low or undetectable levels after 6 years. In contrast, serum anionic trypsinogen levels remained normal or elevated in 33% of those over 6 years of age. There was no age-related change in either cationic or anionic trypsinogen among the CF patients with pancreatic sufficiency, and the majority had normal or elevated levels. Serum samples from selected CF patients were separated into IgG and non-IgG fractions using Staph. Protein A columns. Immunoreactive cationic and anionic trypsinogen were detectable in the non-IgG fractions of sera from CF infants and older patients with pancreatic sufficiency. In older CF patients with undetectable serum cationic and anionic trypsinogen, no immunoreactive material was detectable in either the IgG or non-IgG fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Aging; Anions; Cations; Child; Cystic Fibrosis; False Positive Reactions; Female; Humans; Immunoglobulin G; Male; Pancreas; Radioimmunoassay; Trypsinogen

Indirect and qualitative tests of pancreatic function are commonly used to screen patients with cystic fibrosis for pancreatic insufficiency. In an attempt to develop a more quantitative assessment, we compared the usefulness of measuring serum pancreatic lipase using a newly developed enzyme-linked immunosorbent immunoassay with that of cationic trypsinogen using a radioimmunoassay in the assessment of exocrine pancreatic function in patients with cystic fibrosis. Previously, we have shown neither lipase nor trypsinogen to be of use in assessing pancreatic function prior to 5 years of age because the majority of patients with cystic fibrosis in early infancy have elevated serum levels regardless of pancreatic function. Therefore, we studied 77 patients with cystic fibrosis older than 5 years of age, 41 with steatorrhea and 36 without steatorrhea. In addition, 28 of 77 patients consented to undergo a quantitative pancreatic stimulation test. There was a significant difference between the steatorrheic and nonsteatorrheic patients with the steatorrheic group having lower lipase and trypsinogen values than the nonsteatorrheic group (P less than .001). Sensitivities and specificities in detecting steatorrhea were 95% and 86%, respectively, for lipase and 93% and 92%, respectively, for trypsinogen. No correlations were found between the serum levels of lipase and trypsinogen and their respective duodenal concentrations because of abnormally high serum levels of both enzymes found in some nonsteatorrheic patients. We conclude from this study that both serum lipase and trypsinogen levels accurately detect steatorrhea in patients with cystic fibrosis who are older than 5 years but are imprecise indicators of specific pancreatic exocrine function above the level needed for normal fat absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Cations; Celiac Disease; Child; Child, Preschool; Cystic Fibrosis; Dietary Fats; Enzyme-Linked Immunosorbent Assay; Feces; Female; Gastrointestinal Contents; Humans; Lipase; Male; Pancreas; Radioimmunoassay; Trypsin; Trypsinogen

Serum immunoreactive pancreatic lipase and cationic trypsinogen are elevated in young infants with cystic fibrosis (CF) and may be useful neonatal screening tests for CF. We compared lipase measured by a recently developed ELISA immunoassay with trypsinogen measured by radioimmunoassay in 70 children (ages 0.1 to 9.9 years) with CF who had various degrees of pancreatic dysfunction and in 79 similarly aged children without CF (controls). In the control children, lipase activity increased with advancing age, whereas trypsinogen showed no age-related trend. Lipase and trypsinogen were significantly elevated in the infants with CF who were younger than 1 year, irrespective of pancreatic function (trypsinogen, P less than 0.001; lipase, P less than 0.05). Sensitivities in detecting CF were 76% and 90% for lipase and trypsinogen, respectively. After the first year of life, lipase and trypsinogen values declined toward normal, the rate of decline of lipase being greater than that of trypsinogen; 67% of lipase values were within or below the normal range by 3 years, whereas 67% of trypsinogen values continued to be elevated. We conclude that trypsinogen is an excellent screening test for CF in young infants regardless of pancreatic function, and that the addition of a serum pancreatic lipase determination does not improve the accuracy of trypsinogen as a screening test for cystic fibrosis.

Topics: Age Factors; Child; Child, Preschool; Cystic Fibrosis; Fetal Blood; Humans; Infant; Infant, Newborn; Lipase; Pancreas; Trypsinogen

Topics: Cystic Fibrosis; Humans; Infant, Newborn; Mass Screening; Trypsinogen

Serological tests used in pancreatic diseases, especially isoamylase analysis and trypsin radioimmunoassay are presented. The results show that these markers are helpful in the diagnosis of chronic pancreatic diseases.

Topics: Adolescent; Amylases; Child; Child, Preschool; Chronic Disease; Cystic Fibrosis; Humans; Infant; Isoenzymes; Lipase; Pancreatic Diseases; Trypsinogen

Topics: Cystic Fibrosis; Decision Making; False Negative Reactions; False Positive Reactions; Female; Genetic Counseling; Humans; Infant; Parent-Child Relations; Pregnancy; Prenatal Diagnosis; Trypsinogen

Topics: alpha-Amylases; Cholecystokinin; Cystic Fibrosis; Female; Heterozygote; Humans; Male; Pancreatin; Secretin; Trypsinogen

In 4,956 infants the concentration of immunoreactive trypsin was measured in dried blood on filter paper using a double antibody radio immuno assay. About 90% of all results were below 40 ng/ml. In 13 infants the concentration of immunoreactive trypsin exceeded 80 ng/ml. These infants were examined clinically, including sweat iontophoresis. We found three children suffering from cystic fibrosis. One further child showing an elevated concentration of chloride in the sweat (60 mval/ml) could not be reexamined. The concentration of immunoreactive trypsin in the cystic fibrosis children was 230, 297, and in one case 108 ng/ml at the 76th day of life, whereas the values for the 9 other children were between 80 and 154 ng/ml. We believe these results justify to use this test for a much higher number of infants, especially because it is inexpensive and can easily be added to existing newborn screening programs for inborn errors of metabolism.

Topics: Cystic Fibrosis; Humans; Infant, Newborn; Radioimmunoassay; Reference Values; Time Factors; Trypsin; Trypsinogen

The capacities of normal and cystic fibrosis (CF) sera to bind to exogenous human [125I]trypsin were compared. Sera from eight older CF patients bound significantly more exogenous human [125I]trypsin than did sera from eight normal subjects (p less than 0.001). Disregarding the increased trypsin-binding (TB) of CF sera, serum immunoreactive trypsinogen (SIRT) levels were not detectable in these eight older CF patients. However, when SIRT levels were corrected for TB, four CF patients had normal SIRT concentrations and four had low but detectable SIRT levels. As compared to five normal newborns' sera, serum from a newborn with CF had normal TB and the SIRT levels were very high. In conclusion, increased TB in CF serum lowers results of SIRT assays. Therefore, unless SIRT levels are corrected for TB, results obtained from currently available SIRT kits may be invalid.

Topics: Adolescent; Adult; Antigens; Child; Child, Preschool; Cystic Fibrosis; Female; Humans; Iodine Radioisotopes; Male; Radioimmunoassay; Trypsin; Trypsinogen

Previous data from this laboratory have shown good correlation between plasma cationic trypsin(ogen) and levels of pancreatic function in older cystic fibrosis (CF) patients with and without malabsorption. In the present study a radioimmunoassay for human anionic trypsin(ogen) has been employed in the assessment of pancreatic function in older patients with CF. Immunoreactive anionic trypsin(ogen) levels correlated poorly with pancreatic function due to an apparent elevation of this enzyme in many older CF patients with malabsorption (CF + M). When plasma from three older CF + M patients is examined for the molecular size of the apparent immunoreactive material detected, no free anionic trypsinogen is observed. Instead, a broad peak of apparent immunoreactive material appears in the gammaglobulin region. However, only free anionic trypsinogen could be detected in plasma from two CF patients without malabsorption (CF - M), who had not received pancreatic enzyme supplements. It appears possible that a human plasma immunoglobulin G (IgG) to porcine pancreatic enzyme in the CF + M patients might interfere in the assay by binding TLCK--anionic trypsin tracer. It is unclear why such an effect does not appear to occur in the cationic trypsin(ogen) assay. The results of the current study suggest that, for assessment of pancreatic insufficiency in CF, the radioimmunoassay for cationic trypsin(ogen) is more useful than the presently available radioimmunoassay for the anionic form.

Topics: Adolescent; Adult; Anions; Child; Cystic Fibrosis; Duodenum; Humans; Intestinal Secretions; Radioimmunoassay; Trypsin; Trypsinogen

Plasma immunoreactive cationic trypsin(ogen) levels were determined in 32 control subjects and 43 patients with varying degrees of pancreatic insufficiency including 35 with cystic fibrosis (CF) and eight with Shwachman's syndrome. In six CF infants less than 2 years of age, plasma trypsin(ogen) levels were significantly elevated (97.3 +/- 62.2 ng/ml) above the normal range for nine controls (7.0 +/- 5.9 ng/ml; P less than 0.025). Four of these infants had steatorrhea, three of whom had undetectable duodenal trypsin activity after stimulation with secretin-cholecystokinin. In two CF infants, molecular size fractionation by gel filtration of plasma followed by radioimmunoassay of the column fractions demonstrated that trypsinogen was the only immunoreactive species in the circulation. In contrast, in older CF patients with steatorrhea (mean age, 15.3 +/- 4.6 years), plasma cationic trypsin(ogen) levels were undetectable or low (1.1 +/- 1.7 ng/ml). This finding clearly distinguished them from older CF patients without steatorrhea (mean age, 14.3 +/- 3.9 years) in whom cationic trypsin(ogen) levels were significantly higher (23.3 +/- 17.6 ng/ml; P less than 0.01). The mean trypsin(ogen) concentration in the older CF patients without steatorrhea did not differ from the mean value for 23 normal subjects of similar age. Plasma cationic trypsin(ogen) levels in two Schwachman's patients with steatorrhea (0.19 and 0.86 ng/ml) were significantly lower than the values found in six Shwachman's patients without steatorrhea (5.9 +/- 2.3 ng/ml; P less than 0.025). Furthermore, in nine older CF patients and eight Schwachman's patients, circulating trypsin(ogen) levels were highly correlated with duodenal trypsin output after secretin-cholecystokinin stimulation (r = 0.946, P less than 0.01; r = 0.899, P less than 0.01, respectively). These results suggest that in CF infants high levels of circulating trypsin(ogen) persist even in those with Shwachman's syndrome, however, circulating trypsin(ogen) accurately reflects residual pancreatic function.

Topics: Adolescent; Adult; Child; Child, Preschool; Cystic Fibrosis; Exocrine Pancreatic Insufficiency; Female; Humans; Infant; Male; Radioimmunoassay; Syndrome; Trypsin; Trypsinogen

Exocrine pancreatic insufficiency usually does not develop before reduction of enzyme output by more than 90%. Patients with pancreatic insufficiency have a ravenous appetite but fail to thrive from malnutrition. The caloric deprivation is primarily due to fat malabsorption, recognized by the passage of bulky foul smelling greasy stools. Several isolated enzyme deficiencies can be separated from diseases with generalised pancreatic insufficiency. Under replacement therapy with pancreatic enzyme supplements most patients improve and gain weight, although fat and bile acid malabsorption are not abolished.

Topics: Amino Acid Metabolism, Inborn Errors; Amylases; Cystic Fibrosis; Enteropeptidase; Enzyme Therapy; Exocrine Pancreatic Insufficiency; Humans; Intestinal Absorption; Kwashiorkor; Lipase; Lipid Metabolism; Malabsorption Syndromes; Trypsinogen

Topics: Amylases; Child; Cystic Fibrosis; Enteropeptidase; Humans; Infant; Methods; Neutropenia; Pancreas; Pancreatic Cyst; Pancreatic Diseases; Pancreatic Neoplasms; Pancreatitis; Peptide Hydrolases; Syndrome; Trypsinogen