Which cardiac marker is the test of choice for MI, appearing 2-6 hours after an event?

Troponin is the test of choice for diagnosing myocardial infarction (MI) due to its high specificity and sensitivity for cardiac muscle injury. Specifically, cardiac troponin I and T levels typically start to rise within 2 to 6 hours following an acute MI, peaking at about 24 hours, and can remain elevated for several days. This makes troponin test results particularly useful for both early diagnosis and assessing ongoing myocardial injury.

While other markers such as creatine kinase MB (CK-MB) and myoglobin also play roles in the diagnostic process, they do not provide the same level of specificity or reliability within the specified timeframe. Myoglobin, for instance, can rise quickly (within 2 hours) but lacks specificity for cardiac tissue as it is also released from skeletal muscle. CK-MB is more specific than myoglobin but generally peaks later and is not as sensitive as troponin for detecting smaller infarctions.

B-type natriuretic peptide (BNP) is primarily used to assess heart failure rather than acute coronary events, further underscoring why troponin is favored for acute MI evaluation. The unique characteristics of troponin, therefore, establish it as the standard biomarker used in clinical practice for timely