Which cardiac biomarker is elevated in MI?

• A. Troponin
• B. C-Reactive Protein
• C. D-dimer
• D. BNP

Answer: (A)

Cardiac troponin I or T is the biomarker elevated when heart muscle is damaged in a myocardial infarction. It’s highly specific to cardiac tissue, so its release into the blood after myocardial injury makes it the most reliable indicator for an MI. The timing is helpful clinically: troponin rises within a few hours, peaks around 12–24 hours, and remains elevated for days, allowing diagnosis even if the patient presents after several hours.

C-reactive protein rises with inflammation and is not specific to heart muscle injury. D-dimer indicates clot breakdown and is used to assess for thrombotic events like PE or DVT, not MI itself. BNP increases with ventricular stretch and heart failure, not acute myocardial infarction.