Comparative study of cardiac troponin I and T measurements in a routine extra-cardiological clinical setting.

This study compared troponin I (cTnI) to troponin T (cTnT) in a population admitted to General Medicine Divisions in whom acute myocardial infarction (AMI) was suspected; 98 consecutive patients were included. Diagnoses were made without knowledge of troponin results: 51 patients had AMI, and 47 (including 8 with unstable angina) had no AMI. Patients were considered to be troponin positive if the marker concentration was >99th percentile value of the reference population. Both troponins were associated with an almost absolute sensitivity for AMI (100% for cTnI and 98.0% for cTnT), while the specificity was marginally higher for cTnI (78.7% vs. 68.1%). Increased cTnI and/or cTnT were observed in 15 patients out of 39 without acute coronary syndromes. Simultaneous positivity was seen in 8 patients with severe disorders and complications. Discordances were more frequent in favor of increased cTnT (n = 5) than the opposite (n = 2), even if this difference did not achieve statistical significance. cTnI and cTnT detected AMI with comparable efficiency. Cases without coronary syndrome positively concordant for troponins confirmed the ability of these biomarkers to detect myocardial injury undetectable by conventional diagnostic approaches.