What is troponin and why is it important in cardiac assessment?

Troponin is a protein found in cardiac muscle cells that is released into the bloodstream when heart muscle is damaged. It is the most sensitive and specific biomarker for myocardial infarction. Troponin I and troponin T are the two forms tested. Levels begin rising within two to four hours of cardiac injury, peak at 12 to 24 hours, and remain elevated for 7 to 14 days. A positive troponin in a patient with chest pain confirms myocardial injury. Serial troponin levels are drawn at presentation and repeated at three to six hour intervals to detect a rising pattern that confirms acute MI.