creatine kinase

The creatine kinase - An enzyme (a protein that alters the rate of a chemical reaction in the body) found in muscle. After damage to muscle cells, including those of the heart muscle, creatine kinase leaks into the blood.

Increased levels of the enzyme can be detected by diagnostic tests (see muscle enzymes). Different types of creatine kinase exist in different types of muscle. If blood tests show a raised level of the form found in heart muscle, this may indicate that a myocardial infarction (heart attack) has occurred.

Raised levels of the form found in skeletal muscles may indicate a range of disorders, from muscle injury to diseases such as muscular dystrophy.