The comparative analytical performance of four troponin I assays at low concentration

Background: Low troponin concentrations have been shown to be informative in the prognosis of acute coronary syndrome. We have investigated the analytical performance of four commonly used cardiac troponin I methods at concentrations approaching their analytical limit of detection. Method: We assayed 167 patient samples within 24 h of collection using the Beckman Coulter AccuTnl, Dade Behring Dimension, Abbott AxSYM and Bayer Centaur methods and compared their relative analytical performance. Results: Of the four assays compared, the AccuTnl was observed to have greater sensitivity at low concentrations. Using the limit of detection as the threshold, the Beckman assay showed superior performance at concentrations corresponding to a 20% coefficient of variation (CV), the Dade assay had a similar performance; and at concentrations corresponding to 10% CV most assays provide similar information. Conclusion: The newer or recently modified assays such as the Beckman Coulter AccuTnl and Dade Behring assays are best able to identify very low concentrations of troponin.