ABSTRACT
OBJECTIVES: This paper evaluates the effect of hemoglobin (Hb) and hemolysis on insulin measurements with the Architect-Ci8200 analyzer. DESIGN AND METHODS: Insulin concentrations were measured using the Architect-Ci8200. Interference studies were performed by spiking serum pools of defined insulin concentrations with increasing concentrations of either free Hb or hemolysate. A change of more than 10% was taken as evidence of significant interference. RESULTS: A significant negative bias in insulin results was observed only in samples spiked with hemolysate but not with free Hb. The bias was proportional to the degree of hemolysis and to the time elapsed before insulin assay. This interference was decreased when samples were kept at +4°C. CONCLUSIONS: For all insulin requests, hemolysis must be systematically checked before biological interpretation of insulin results.
Subject(s)
Hemoglobins/metabolism , Hemolysis , Immunoassay/instrumentation , Immunoassay/methods , Insulin/metabolism , Humans , Temperature , Time FactorsABSTRACT
BACKGROUND AND METHODS: Cardiac troponin I (cTnl) is well recognized as a specific marker for myocardial infarction. A fully automated, random access, fluorescent immunoassay for cTnl was evaluated in comparison with an established assay (Stratus cTnl) using samples from healthy subjects and from patients with cardiac disease. RESULTS: The detection and precision were acceptable, and no interference was observed from bilirubin, triglycerides, haemoglobin, rheumatoid factor, drugs (aspirin, dopamine, digoxin) or heparin. Results on the Kryptor cTnl assay correlated with those on the Stratus II cTnI assay. The optimum Kryptor cTnl concentration for acute myocardial infarction was 0.63 microg/L, with a sensitivity of 89% [95% confidence interval (CI): 75.9-96.3] and specificity of 98.9% (95% CI: 93.9-99.8). CONCLUSION: Kryptor cTnl immunoassay is suitable for use in the diagnosis of myocardial infarction.
