salicylates and ferric-chloride

Ferric chloride (FC) and Trinder reagent (TR) have both been used to identify salicylates (ASA) in the urine of patients presenting with possible drug overdose. The authors sought to compare the sensitivities and specificities of these two reagents in detecting ASA in the urine of patients presenting to an emergency department (ED) with suspected drug overdose.. Patients were eligible for inclusion in this study if they presented to the ED with either suspected overdose or unexplained metabolic acidosis. One milliliter of the patient's urine was added to 1 mL of each of the two reagents. A positive test was defined as any darkening of the color of the reagent. Each patient had a quantitative serum ASA measured.. Twenty of 180 patients (11%) had quantitative serum ASA levels above 5 mg/dL. Both reagents were 100% sensitive in identifying these patients. The specificity of FC was 71% compared with 73% for TR. The two reagents gave similar results in 91% of cases.. Both FC and TR are reliable in detecting ASA in the urine of patients presenting with suspected drug overdose. A negative result with either test eliminates the need for a quantitative serum ASA level. Because FC has a longer shelf life than TR, it is the more practical reagent for use in the ED.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Chlorides; Confidence Intervals; Drug Overdose; Emergency Service, Hospital; False Positive Reactions; Female; Ferric Compounds; Humans; Indicators and Reagents; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Salicylates; Sensitivity and Specificity

Ferric chloride (FeCl3) is used to qualitatively test the urine of patients with presumed salicylate exposure. FeCl3 testing of an unidentified poison might provide evidence of salicylate exposure in situations where FeCl3 urine testing cannot be used. Such situations include the absence of a urine sample, immediately after ingestion before urine contains a detectable quantity of salicylate, or for patients chronically using salicylatesfor which FeCl3 testing is unhelpful. This study seeks to determine if FeCl3 can be used to identify salicylate-containing products.. We assessed the reactivity of FeCl3 with commercially available salicylate-containing products. We applied 0.1 mL of 10% FeCl3 solution to each of 15 various salicylate-containing products including: regular and buffered acetylsalicylic acid, bismuth subsalicylate, methylsalicylate, physostigmine salicylate, salicylic acid, trolamine salicylate, and herbal tablets with salicin-containing white willow bark (Salix sp.). These products tested were: regular and enteric-coatedpills (n = 4), powder (n = 1), topical creams (n = 5), topical liquids (n = 4), and intravenous solution (n = 1). FeCl3 was applied to crushed tablets and added directly to liquids and creams. Fifteen salicylate-free controls including liquids, pills, and creams similar in appearance to experimental samples were also tested. Three blinded physiciansfamiliar with FeCl3 testing independently observed the addition of FeCl3 to each sample and rated a positive or negative result.. All salicylate-containing products were interpreted to be clearly FeCl3 positive and all control samples were interpreted to be clearly FeCl3 negative.. Salicylate-containing products may be identified using FeCl33. When using FeCl3

Topics: Chemistry, Pharmaceutical; Chlorides; Drug Contamination; Ferric Compounds; Humans; Salicylates

Topics: Chlorides; Ferric Compounds; Humans; Salicylates

Patients with Reye's syndrome who have been given aspirin are said to maintain higher-than-anticipated salicylate concentrations in blood, for longer than expected. We explored whether this could be attributed to spurious results from nonsalicylate compounds in the Trinder reaction for salicylates. All of 63 organic acids and amines examined that form colored complexes with Trinder's reagent had detectable absorbance at 540 nm at 0.2 g/L, including some endogenous compounds known to be increased in Reye's syndrome patients and many others endogenous in humans. By subjecting deproteinized sera to thin-layer chromatography and eluting the salicylate fraction before complexing it with ferric ion, true salicylate can be measured quantitatively and differentiated from interfering compounds. In addition, when we examined the effect of salicylate on palmitate binding to serum proteins, we found that salicylate concentrations of 0.2 g/L displaced [16-14C]palmitate binding to protein more in Reye's syndrome patients than in Reye's syndrome survivors or children with influenza. This suggests the presence of atypical binding characteristics for salicylate and palmitate in the acute disorder but not in survivors or children with influenza.

Topics: Aspirin; Blood Proteins; Child; Chlorides; Chromatography, Thin Layer; False Positive Reactions; Ferric Compounds; Humans; Palmitates; Protein Binding; Reye Syndrome; Salicylates; Spectrophotometry