Performance Evaluation of the Point-of-Care Cardiac Troponin T Assay

ABSTRACT

BACKGROUND: The point-of-care (POC) troponin T assay has been used in various clinical settings. Recently, a POC troponin T assay with an extended measurable range (40 ng/L-2,000 ng/L) was introduced. We aimed to evaluate the analytical performance of the Roche Cardiac POC Troponin T assay (POC TnT, Roche Diagnostics, Switzerland) using the cobas h 232 POC system. METHODS: The repeatability and within-laboratory imprecision of the POC TnT assay were evaluated using the Roche Cardiac POC Troponin T level 2 control. Repeatability was also assessed using patient samples. Linearity of the POC TnT assay was evaluated using patient samples containing five different concentrations of troponin T. Performance of the Elecsys Troponin T high sensitivity assay (hs-TnT) was compared with that of the POC TnT assay using 40 patient samples. RESULTS: The repeatability (%CV), and within-laboratory imprecision (%CV) using the level 2 control solution (mean troponin T, 441.6 ng/L) were 8.5% and 8.6%, respectively. The repeatability of patient samples containing 88.7 ng/L and 454.6 ng/L TnT was 7.5% and 7.2%, respectively. The POC TnT assay was confirmed to produce linear data between 54.0 ng/L and 1,347.7 ng/L. Relative to the hs-TnT assay, the Passing-Bablok linear regression equation (correlation coefficient) was y=0.8933x+6.24 (r=0.988). At a troponin T concentration of 40 ng/L, the estimated bias of the POC TnT assay was 1.972 ng/L (4.93%). CONCLUSIONS: Our data suggest that the Roche Cardiac POC Troponin T assay is reliable in cases where POC troponin T testing is required.