Cardiac troponin T and I are highly specific markers for detecting myocardial damage and risk stratification, though they lack sensitivity in the first hours of acute coronary syndromes.
Cardiac troponins T and I are highly specific markers for myocardial injury and risk stratification, but their delayed rise necessitates the concurrent use of an early marker in the acute setting.
The troponin (Tn) complex consists of three subunits referred to as TnT, TnI and TnC. Myocardium contains TnT and TnI isoforms which are not present in skeletal muscles and which can be separated from the muscular isoforms by immunological techniques. Using commercially available immunoassays, clinical laboratories are able to determine cardiac TnT and TnI (cTnT and cTnI) quickly and reliably as classical cardiac markers. After acute myocardial infarction, cTnT and cTnI concentrations start to increase in serum in a rather similar way than CK-MB, but return to normal after longer periods of time (approximately one week). Because of their excellent cardiac specificity, Tn subunits appear ideally suited for the differential diagnosis of myocardial and muscular damage, for example in noncardiac surgery patients, in patients with muscular trauma or with chronic muscular diseases, or after intense physical exercise. cTnT and cTnI may also be used for detecting evidence of minor myocardial damage: therefore they have found new clinical applications, in particular risk stratification in patients with unstable angina. In spite of the possible reexpression of cTnT in human skeletal muscles, and of the lack of standardization of cTnI assays, Tn subunits are not far to meet the criteria of ideal markers for acute myocardial injury. Only an insufficient sensitivity in the first hours following the acute coronary syndroms requiries to maintain an early myocardial marker in the cardiac panel for routine laboratory testing.
Jean-Paul Chapelle (Fri,) conducted a review in Myocardial damage and acute myocardial infarction. Cardiac Troponin I and Troponin T was evaluated. Cardiac troponin T and I are highly specific markers for detecting myocardial damage and risk stratification, though they lack sensitivity in the first hours of acute coronary syndromes.