What is considered the gold standard biomarker for acute myocardial infarction?

• A. Troponins
• B. CK-MB
• C. Myoglobin
• D. BNP

Answer: (A)

Troponins are the protein complex released when heart muscle cells are damaged, making them the most specific and sensitive marker of myocardial injury. Their high cardiac specificity means elevations are due to heart muscle damage rather than injury elsewhere, and high-sensitivity assays can detect even small infarcts early. After a myocardial infarction, troponin levels rise within about 3–4 hours, peak around 12–24 hours, and remain elevated for several days, sometimes longer, which helps confirm the diagnosis when checked in serial tests. This combination of cardiac-specific detection and a reliable rise-and-fall pattern is why troponin has become the standard biomarker for acute MI.

Other markers have limitations. CK-MB is less specific because it can come from skeletal muscle and can be elevated in non-ischemic conditions; it also rises later and clears more quickly. Myoglobin is an early marker but is not specific to the heart. BNP reflects ventricular stress and is used more in assessing heart failure than diagnosing an MI.