WHAT IS CREATINE KINASE (CK) TEST?
Creatine kinase is an enzyme found in muscle and brain tissue and reflects tissue catabolism as a result of cell trauma. It catalyses creatine-creatinine metabolism. The test is performed to detect myocardial or skeletal muscle damage or central nervous system damage, resulting in increased tissue catabolism from those areas. One can determine what type of tissue damage (tissue undergoing increased catabolism) has occurred by performing the CK isoenzyme test; this test measures the three types of isoenzymes that make up total CPK: CK1-BB, CK2-MB, and CK3-MM. CK1-BB is found mainly in brain tissue but also in smooth muscle, thyroid gland, lungs, and prostate gland. CK2-MB is found mainly in cardiac muscle but also in the tongue, diaphragm, and skeletal muscle (scant amount). CK3-MM is found mainly in skeletal muscle. The isoenzyme test is usually repeated at 8- to 12-hour intervals to track trends characteristic of specific types of cell damage. Most recently, test kits have been developed to allow detection of CK3-MM and CK2-MB isoforms earlier than the traditional methods for CK isoenzyme detection.