Creatine kinase

Creatine kinase (CK) is an enzyme found primarily in skeletal muscle, heart muscle, and brain tissue. When measured in serum or plasma, elevated CK indicates tissue damage—most commonly muscle injury from trauma, intense exercise, or rhabdomyolysis. CK is also a key cardiac biomarker: the CK-MB isoform rises after myocardial infarction. Serial CK measurements help monitor the progression of muscular dystrophies and the response to statin therapy. CK is one of the most commonly ordered enzymes in emergency and sports medicine settings.