A-009 Analytical Concordance of High-Sensitivity Cardiac Troponin I and T Assays in Patients From the CONTRAST Trial Presenting to an Emergency Department

Abstract Background There are limited data on the analytical concordance of high-sensitivity cardiac troponin (hs-cTn) T and hs-cTnI assays. The goal of this study was to evaluate the concordance of one hs-cTnT and one hs-cTnI assay relative to each assay’s limit of quantitation (LoQ) and 99th percentile upper reference limit (URL). Methods The Comparison of Troponin I and T Assays Trial (CONTRAST) NCT03214029 is an observational study that evaluated the concordance of two FDA-cleared hs-cTn assay concentrations measured at presentation (0 h) and 2 h by the Abbott ARCHITETCT i2000 hs-cTnI (clinically used assay) and Roche cobas 601 Gen 5 hs-cTnT (measured for investigational purposes) from consecutively enrolled patients presenting to an urban US medical center with symptoms suggestive of ischemia. Concordance at presentation (0 h) was assessed relative to each assay’s FDA-cleared reporting concentration (LoQ), and FDA-cleared sex-specific 99th percentile URLs. The incidence of myocardial injury, defined as at least one concentration above the 99th percentile URL over serial sampling, was also evaluated. Results At presentation hs-cTn concentrations <LoQs (Abbott 3.5 ng/L, Roche 6 ng/L) were 834/2270 (37%) and 530/2270 (23%), respectively. The concordance of results <LoQ was 81%. The Abbott assay showed a higher percent of concentrations below both female and male URLs than did the Roche assay. For females, concentrations below the sex-specific 99th percentile URLs were 707/945 (75%) for Abbott hs-cTnI (16 ng/L) and 545/945 (58%) for Roche hs-cTnT (14 ng/L, P < 0.03). For males, concentrations below the sex-specific 99th percentile URLs were 1100/1325 (83%) for Abbott hs-cTnI (34 ng/L) and 900/1325 (68%) for Roche hs-cTnT (22 ng/L). The concordance of results below the sex-specific 99th percentile URLs for both assays was 80%. Among males with presentation concentrations <URL, the incidence of myocardial injury (hs-cTn >URL at 2 h) was approximately two-fold greater for the Roche hs-cTnT (59/900, 6.2%) than Abbott hs-cTnI (31/1110, 2.8%). Females with presentation concentrations <URL showed similar rates of myocardial injury at 2 h for the Roche (24/545 [4.4%]) and Abbott assays (36/707 [5.1%]). Conclusion We report a 20% discordance between Abbott hs-cTnI and Roche hs-cTnT assays in detecting myocardial injury at respective 99th percentile URLs and at each assays’ FDA allowed LoQ reporting limit.