Evaluation of four sensitive troponin assays for risk assessment in acute coronary syndromes using a new clinically oriented approach for comparison of assays.
BACKGROUND
Measurement of cardiac troponin T or I (cTnT; cTnI) is useful for risk prediction in acute coronary syndromes. The objective of the present study was to compare the prognostic capacity of four sensitive cardiac troponin assays using a new method for comparison.


METHODS
Cardiac troponin was analyzed in serum samples from 1335 patients with acute coronary syndrome using the Elecsys high sensitivity TnT (hs-cTnT), ARCHITECT STAT high sensitivity TnI (hs-cTnI), Access AccuTnI (Acc-cTnI) and Architect cTnI (Arc-cTnI) assays. All patients were followed for 30 days regarding death and acute myocardial infarction (AMI), and for 1 year regarding mortality.


RESULTS
By receiver operating characteristic (ROC) curve analyses, there were only minor differences in the area under the curves (AUC) between the assays. At a given sensitivity of 85% the hs-cTnT, Arc-cTnI and Acc-cTnI assays showed comparable specificities, while 90% or higher sensitivity was only possible to achieve with the hs-cTnT, hs-cTnI and Acc-cTnI assays. The highest odds ratios for death/AMI at 30 days and death at 1 year, respectively, were reached by cut-off levels yielding 95% sensitivity; these cut-off levels were below the respective 99th percentile levels.


CONCLUSIONS
By the adoption of a new method for the comparison of cardiac troponin assays we showed that the hs-cTnT, hs-cTnI and Acc-cTnI assays had comparable prognostic properties, while the Arc-cTnI assay had inferior prognostic sensitivity.