Comparison of cardiac troponin T and troponin I assays--implications of analytical and biochemical differences on clinical performance

The usefulness of cardiac troponins for detection of myocardial cell necrosis and risk stratification has been established beyond doubt. Cardiac troponin testing is a key diagnostic element for the diagnosis and management of patients with acute coronary syndromes without ST segment elevation and is increasingly used in non-coronary diseases to indicate prognostically important cardiac damage. Given the biochemical and analytical differences of cTnT and cTnI there is ongoing controversy regarding the comparability and clinical performance of cTnT and cTnI. cTnT and cTnI are both expressed in cardiomyocytes but differ with respect to biochemical and analytical characteristics. While minor differences of analytical precision or biochemical properties are not relevant for diagnosis and management of patients with acute coronary syndromes and most diseases with non-coronary related elevations of cardiac troponins, these differences may be amplified in patients with chronic renal failure. In fact, recent studies in patients with end-stage renal disease under chronic hemodialysis have readdressed the issue whether cTnT and cTnI are really comparable. The present review will provide a state-of-the-art overview on the performance of cardiac troponins in acute coronary disease and other clinical conditions.