CK-MB
Also written as: CK-MB — creatine kinase-MB
Creatine kinase-MB isoenzyme, a cardiac biomarker used to detect myocardial injury, though largely superseded by troponin.
Full Definition
Creatine kinase-MB (CK-MB) is an isoenzyme of creatine kinase that is relatively specific to cardiac muscle and was historically used as a biomarker for myocardial infarction. CK-MB levels begin to rise 3-6 hours after myocardial injury, peak at 12-24 hours, and return to normal within 2-3 days. While CK-MB was once the gold standard for diagnosing acute myocardial infarction, it has been largely replaced by cardiac troponins due to their superior sensitivity and specificity. CK-MB may still be useful for detecting reinfarction due to its shorter half-life compared to troponin. The test measures both total CK-MB mass and relative index (percentage of total CK).
Usage
Usage note: Less commonly used than troponin in contemporary practice but may appear in older literature.
In Context
- "CK-MB levels peaked at 18 hours post-presentation, consistent with myocardial infarction." — laboratory report
- "Serial CK-MB measurements were used to assess the extent of myocardial damage." — progress note