Creatine Kinase and Isoenzymes
Test Description: Creatine kinase (CK) is an enzyme found primarily in the heart and skeletal muscles, and in smaller amounts in the brain. When the total CK level is substantially elevated, it usually indicates injury or stress to one or more of these areas. When a muscle is damaged, CK leaks into the bloodstream. Determining which isoenzyme (specific form of CK) is elevated will help determine which tissue has been damaged. CK can be measured as the total enzyme in the serum, or each of its three isoenzymes may be measured. The isoenzymes include: CK1 (CPK-BB): produced primarily by brain tissue and smooth muscle of the lungs CK2 (CPK-MB): produced primarily by heart tissue CK3 (CPK-MM): produced primarily by skeletal muscle CK, along with asparate aminotransferase (AST) and troponin, is assessed in the case of suspected myocardial infarction. It typically appears in the bloodstream within 3 to 6 hours of the tissue injury, with peak values occurring 18 to 24 hour...