Which cardiac marker is indicative of myocardial infarction?

Troponin I is a highly specific cardiac marker used to diagnose myocardial infarction (MI). It is a protein found in cardiac muscle that is released into the bloodstream when the heart muscle is damaged. In cases of myocardial infarction, levels of Troponin I increase significantly and can remain elevated for several days, making it an invaluable tool for diagnosing acute coronary syndromes.

The reason Troponin I is preferred over other markers is its specificity for cardiac tissue, which allows clinicians to differentiate between cardiac and non-cardiac causes of elevated troponin levels. While other markers like Creatine Kinase (CK) and LDH can indicate muscle damage, they are not specific to the heart and can be affected by a variety of other conditions. B-type Natriuretic Peptide (BNP) is primarily used to assess heart failure rather than myocardial infarction specifically. Therefore, Troponin I is the most reliable marker for diagnosing myocardial infarction and assessing its severity.