kaolinite and Liver-Diseases

Thromboelastography can be performed with native or citrated blood (a surrogate to native blood in healthy controls, surgical and cirrhotic patients). Activators such as kaolin are increasingly used to reduce the time to trace generation. To compare kaolin-activated thromboelastography with nonkaolin-activated thromboelastography of native and citrated blood in patients with liver disease, patients undergoing treatment with warfarin or low-molecular weight heparin and healthy volunteers. We studied thromboelastography parameters in 21 healthy volunteers (group 1) and 50 patients, including 20 patients with liver cirrhosis with a nonbiliary aetiology (group 2), 10 patients with primary biliary cirrhosis or primary sclerosing cholangitis (group 3), 10 patients on warfarin treatment (group 4) and 10 patients with enoxaparin prophylaxis (group 5). Thromboelastography was performed using four methods: native blood (kaolin-activated and nonkaolin-activated) and citrated blood (kaolin-activated and nonkaolin-activated). For all thromboelastography parameters, correlation was poor (Spearman correlation coefficient < 0.70) between nonkaolin-activated and kaolin-activated thromboelastography, for both citrated and native blood. In healthy volunteers, in patients with liver disease and in those receiving anticoagulant treatment, there was a poor correlation between nonkaolin-activated and kaolin-activated thromboelastography. Kaolin-activated thromboelastography needs further validation before routine clinical use in these settings, and the specific methodology must be considered in comparing published studies.

Topics: Adult; Aged; Anticoagulants; Artifacts; Blood Specimen Collection; Cholangitis, Sclerosing; Citrates; Enoxaparin; False Positive Reactions; Female; Hepatitis, Viral, Human; Humans; International Normalized Ratio; Kaolin; Liver Cirrhosis; Liver Cirrhosis, Biliary; Liver Diseases; Male; Middle Aged; Reference Standards; Reproducibility of Results; Sensitivity and Specificity; Sodium Citrate; Thrombelastography; Warfarin

The dilute Russell viper venom time and kaolin clotting time (KCT) are very sensitive screening tests for lupus anticoagulant activity. However, due to the high turbidity of the kaolin reagent it is difficult to accommodate the KCT on the optical end point automation of today. We evaluated five recently reported screening tests (the silica clotting time, the Textarin/Ecarin ratio, the Taipan venom time, the factor V ratio, and a kaolin clotting time using low-turbidity kaolin) as potential alternatives to the KCT. The sensitivity and specificity of the silica clotting time compared well to KCT, detecting 10/12 KCT positive samples and showing equal sensitivity to dilution of lupus positive plasma. In addition, the silica clotting time allows for a confirmatory phospholipid correction procedure. False-positive results were seen in 2 of 15 warfarinised samples. A second assay utilising the ratio of extrinsic/intrinsic factor V assays was not affected by either warfarin or heparin. This assay also gave positive results with 3 of 23 samples previously screened as lupus negative but exhibiting anticardiolipin positivity. It was therefore concluded that a combination of the silica clotting time and dilute Russell viper venom time met the requirements of lupus sensitivity with demonstration of phospholipid dependence and optical end point compatibility. The factor V ratio is a useful second-line screen for both anticoagulated patients and anticardiolipin antibody-positive samples.

Topics: Anticoagulants; Antiphospholipid Syndrome; Autoimmune Diseases; Automation; Blood Coagulation Tests; Elapid Venoms; Endopeptidases; Evaluation Studies as Topic; Factor V; False Positive Reactions; Heparin; Humans; Kaolin; Liver Diseases; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Nephelometry and Turbidimetry; Partial Thromboplastin Time; Peptide Hydrolases; Postoperative Period; Prothrombin; Prothrombin Time; Silicon Dioxide; Warfarin

A coupled amidolytic assay for factor VII (VII) has been developed that when used with a clotting assay for VII enables detection of activated VII. In the assay, VII in a test material determines generation of factor Xa in a mixture of purified factor X, tissue factor, and calcium; factor Xa is measured with a chromogenic substrate. Factor VII activity in the coupled amidolytic assay (VIIam) correlated well with VII activity in a one-stage clotting assay (VIIc) in 57 healthy subjects, 5 patients with hereditary VII deficiency, and 11 patients with liver disease. Activation of plasma VII by kaolin, clotting, or cold strikingly increased VIIc but not VIIam levels. Thus the ratio VIIc/VIIam (VII activity ratio) is a measure of VII activation. In 27 warfarin-treated patients the mean VII activity ratio was significantly decreased, reflecting a greater decline in VIIc than in VIIam. This probably stems from partially carboxylated VII being able to act during the 3-min incubation of the amidolytic assay but unable to act rapidly enough to affect the clotting assay. Measurement of VIIc/VIIam should enable evaluation of the activity state of VII in thrombotic disorders and in components for transfusion therapy.

Topics: Blood Preservation; Cold Temperature; Factor VII; Factor X; Humans; Kaolin; Liver Diseases; Methods; Warfarin

Topics: Adult; Angioedema; Arginine; Enzyme Activation; Enzyme Precursors; Esterases; Estrogens; Factor XII; Female; Humans; Hypersensitivity; Kallikreins; Kaolin; Kinins; Liver Diseases; Male; Malignant Carcinoid Syndrome; Middle Aged; Pancreatitis; Shock, Septic