Which cardiac biomarker is commonly used in diagnosing myocardial infarction?

Troponin I is a highly sensitive and specific biomarker for myocardial infarction. It is a protein released into the bloodstream when cardiac muscle cells are damaged, making it an essential tool for diagnosing acute coronary syndromes. Elevated levels of Troponin I can be detected as soon as a few hours after the onset of myocardial injury, and they can remain elevated for several days, allowing for the assessment of myocardial infarction in both acute and delayed presentations.

Creatine kinase is another enzyme that can indicate muscle injury, but it is less specific for the heart compared to Troponin I. It can be elevated in a variety of conditions, including skeletal muscle damage, and therefore is not solely indicative of myocardial infarction.

Brain natriuretic peptide (BNP) is primarily used in diagnosing heart failure rather than myocardial infarction. While it can be elevated in cases of cardiac stress, it does not specifically indicate myocardial injury.

Lactate dehydrogenase is an enzyme that rises in many types of tissue damage and is not specific for myocardial infarction. While it can be used as part of a diagnostic workup, it is not the preferred biomarker for confirming myocardial injury.

In summary, Troponin I is considered the gold standard