Which biomarker is used to distinguish NSTEMI from unstable angina?

• A. Elevated troponin distinguishes NSTEMI from unstable angina
• B. CK-MB is the sole marker used
• C. BNP distinguishes
• D. CRP distinguishes

Answer: (A)

The key idea is that NSTEMI involves myocardial cell death, while unstable angina does not. Cardiac troponins I or T are the most specific markers for heart muscle injury. When myocardial cells die, troponin leaks into the bloodstream, so a rise or elevation in troponin confirms myocardial necrosis and identifies NSTEMI. If troponin stays normal, there isn’t necrosis, which points to unstable angina.

CK-MB can rise with heart muscle injury too, but troponin is more sensitive and specific, making it the preferred marker to distinguish NSTEMI from unstable angina. BNP reflects ventricular stretch and heart failure, not acute necrosis, and CRP is a general inflammatory marker with poor specificity for myocardial infarction, so they don’t reliably differentiate NSTEMI from unstable angina.