Multicenter evaluation of analytical performance of the Liaison troponin I assay.

OBJECTIVES: This study evaluated the analytical characteristics of the Liaison immunoassay for cardiac troponin I (cTnI). DESIGN AND METHODS: The protocol consisted of eight sections: evaluation of antibody specificity, linearity, detection limit and imprecision, method comparison, evaluation of endogenous interferents, anticoagulant interference, sample stability, and reference values. RESULTS: The assay equally measured free and complexed cTnI. The minimum detectable cTnI concentration was 0.021 microg/l. The cTnI concentration corresponding to a total CV of 10% was 0.056 microg/l. Linearity of response was demonstrated along the entire dynamic range of the assay. Assay interferences were minimal. cTnI concentrations in serum and heparinized plasma were significantly different. Values in EDTA plasma were on average approximately 5% higher than in matched serum, but this difference was not significant. The 99th percentile cTnI value in healthy subjects was 0.036 microg/l. CONCLUSIONS: Being sensitive, specific, and precise, the Liaison cTnI assay meets current requirements to aid in the diagnosis of myocardial necrosis.

Evaluation of kryptor cardiac troponin I immunoassay.

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.