Analytical Evaluation of an Automated Immunoassay for Cardiac Troponin I: The Vidas Troponin I Assay

Cardiac troponin I (cTnI) is a sensitive and specific biochemical marker of myocardial damage. We assessed the analytical performance of the Vidas® Troponin I assay (Biomerieux). Controls and serum pools were used to determine the precision, analytical sensitivity and linearity; 97.5 and 99.5 percentiles concentrations were determined from the reference population. Fifty corresponding samples of serum and plasma (lithium-heparin) were tested and the results compared. The in vitro stability of serum and plasma samples was assessed at 20 °C, 4 °C and -20 °C, respectively. Samples of serum were used to assess the agreement between the Vidas® Troponin I method and the revised Dimension RxL cTnI method (Dade-Behring). The total imprecision (CVs) was 13.1-5.2% for concentrations ranging between 0.25 and 19.8 µg/l cTnI. The lower detection limit was 10%). The assay was linear up to 21 g/l. The concentrations in lithium-heparin plasma were higher compared to those of the matched serum samples. The study of the agreement between the Vidas and Dimension RxL cTnI assays showed a total concordance of 96% with a bias value of -0.042. The Vidas® Troponin I test is a fast, precise and sensitive method for the determination of cTnI. Clin Chem Lab Med 2003; 41(10): 13631368