Both cTnI and cTnT are cardiac-specific, rapidly released after injury, remain in circulation for several days, are normally in low concentration in serum or plasma, and can be rapidly assayed at relatively low cost.
Currently, cTnI and cTnT are considered the best markers in diagnosing acute cardiac syndrome (ACS). Either protein can be assayed to detect an AMI or other myocardial injury. These markers are especially helpful when a patient with chest pain and symptoms of an AMI does not have a diagnostic ECG. Both cTnI and cTnT should be considered equal in their performance. However, cTnI is more common as more vendors offer it as an FDA-approved reagent, whereas cTnT was initially patented and thus restricted to only one vendor.
Cardiac troponin levels are used to help diagnose myocardial infarction. Elevations of cardiac troponins are especially significant when other markers are normal. These elevations predict a higher risk of severe cardiac events in the coming month. In other patients with ACS, troponin elevations identify those who are at risk for cardiac events for up to six months.
