Troponin is a cardiac-specific protein released when heart muscle is damaged. It is the gold standard biomarker for diagnosing myocardial infarction. High-sensitivity troponin assays detect cardiac injury within 1-3 hours of chest pain, enabling rapid rule-in or rule-out of heart attack in emergency settings.

Troponin elevation is not exclusive to heart attacks. Myocarditis, pulmonary embolism, sepsis, heart failure, and even strenuous exercise can elevate troponin. The pattern of rise and fall — plus clinical context — determines whether the cause is acute MI or another condition.