Troponin consists of 3 subunits (C, T, and I). Cardiac Troponin I (cTnI) is the only troponin isotope present in the myocardium and is not expressed during any developmental stage in skeletal muscle. Troponin I is released into the bloodstream within hours of the onset of symptoms of myocardial infarction or ischemic damage. It can be detected at 3 to 6 hours following onset of chest pain with peak concentrations at 12 to 16 hours, and remains elevated for 5 to 9 days. cTnI can be used to unmask elevations of cardiac troponin T (cTnT) due to skeletal muscle disease, in which case it will be normal. Positive troponin result may also be found in,
but not limited to, myocarditis, cardiac surgery, angina, unstable angina, congestive heart failure, and noncardiac-related causes, such as, renal failure and pulmonary embolism.
25 Jul