Evaluation of a new ultrasensitive assay for cardiac troponin I

Objectives We evaluated the analytical and clinical performance of a new ultrasensitive cardiac troponin I assay (cTnI) on the ADVIA Centaur® system (TnI-Ultra™). Design and methods The evaluation included the determination of detection limit, within-assay and between-assay variation and comparison with two other non-ultrasensitive methods. Moreover, cTnI was determined in 120 patients with acute chest pain with three methods. To evaluate the ability of the new method to detect MI earlier, it was assayed in 8 MI patients who first tested negative then positive by the other methods. Results The detection limit was 0.009 μg/L and imprecision was < 10% at all concentrations evaluated. In comparison with two other methods, 10% of the anginas diagnosed were recategorized to MI. Conclusions The ADVIA Centaur® TnI-Ultra™ assay presented high reproducibility and high sensitivity. The use of the recommended lower cutpoint (0.044 μg/L) implied an increased and earlier identification of MI.