Performance characteristics of five cardiac Troponin I assays

Background: The aim of this study was to evaluate the performance characteristics of cardiac Troponin I (cTnI) assays on the Access 2, Advia Centaur, Architect i1000(SR), Architect i2000(SR), and Vitros ECi analyzers. Methods: To determine the 99th percentile, plasma and serum samples were drawn from 400 apparently healthy subjects. Functional sensitivity was evaluated by testing 10 panels of serum pools in duplicate for 10 days using 2 reagent lots. Imprecision was also assessed using commercial quality control materials. For method comparison, 100 plasma samples were tested by all methods with the Architect i2000(SR) assay as the comparison method. Results: The 99th percentile ranged from 0.013 to 0.020 mu g/l. Calculated CVs at the 99th percentile were 23-52%. cTnI concentrations at a 10% CV ranged from 0.039 to 0.101 mu g/l. Total CVs determined using quality control materials were 2.4-10.0%. Method comparison results by Deming regression had slopes of 1.03-1.51. The mean bias for cTnI samples between 0.01 and 1.0 mu g/l ranged from 0 to 0.2 mu g/l. Conclusions: No method demonstrated a concentration with a 10% CV that was less than the 99th percentile for healthy adults. All methods compare well to the Architect 12000(SR) assay with the Advia Centaur having the highest positive bias. (C) 2010 Elsevier B.V. All rights reserved.