Cardiac troponins T and I: Biochemical markers in diagnosing myocardial infarction

The cardiac troponins T (cTnT) and I (cTnI) can be measured by immunoassay systems and provide key biochemical information in patients with an acute coronary syndrome. Cardiac troponins are released only after cardiac damage has occurred and are sensitive and specific for myonecrosis. In this article, the clinical role of troponin measurement is illustrated in the diagnosis and management of three categories of patients: those in whom ST segment elevation is shown on the ECG; those with possible acute coronary syndrome at high risk of non-ST elevation acute myocardial infarction; and those with low risk/possible acute coronary syndrome. However, both cTnT and cTnI values can be raised in disorders resulting from causes other than myocardial infarction, for example, in renal failure and after percutaneous coronary intervention. These situations are discussed.