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

Objectives: This study evaluated the analytical characteristics of the Liaison(R) 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 mug/l. The cTnI concentration corresponding to a total CVof 10% was 0.056 mug/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 mug/l. Conclusions: Being sensitive, specific, and precise, the Liaison(R) cTnI assay meets current requirements to aid in the diagnosis of myocardial necrosis. (C) 2004 The Canadian Society of Clinical Chemists. All rights reserved.