Which biomarker is most specific for myocardial injury in the setting of chest pain?

• A. CK-MB
• B. D-dimer
• C. Troponin
• D. BNP

Answer: (C)

Troponin is the biomarker most specific for myocardial injury because cardiac-specific troponin I and troponin T are released into the bloodstream when heart muscle cells are damaged. This makes troponin a highly sensitive and specific indicator of myocardial necrosis, which is why it is central to diagnosing myocardial infarction. After injury, troponin rises within a few hours, peaks around 12–24 hours, and remains elevated for several days, providing a reliable window to detect recent cardiac injury.

CK-MB can rise with myocardial infarction but is less specific because it is also found in skeletal muscle and can be elevated in other conditions involving muscle injury or surgery. D-dimer indicates fibrin breakdown and helps assess thrombotic processes, but it is not specific to the heart and cannot confirm myocardial injury. BNP reflects ventricular wall stress and heart failure rather than acute myocardial injury, so it’s not the best marker for diagnosing myocardial damage in chest pain.

Thus, troponin provides the most specific evidence of myocardial injury in the chest-pain setting and is used in conjunction with the clinical picture and ECG to diagnose acute coronary syndromes.