TROPONIN I

Overview

Troponin I 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. A troponin value above the upper reference limit (99th percentile) value is not always indicative of myocardial infarction. Other conditions resulting in myocardial cell damage can contribute to elevated cardiac troponin I levels. These conditions include, but are not limited to, myocarditis, cardiac surgery, angina, unstable angina, congestive heart failure, and noncardiac-related causes, such as, renal failure and pulmonary embolism.