CK Creatine kinase

Creatine kinase (CK) is a dimeric protein composed of two types of polypeptide chains: B (brain) and M (muscle). Three isoenzymes are distinguished: CK-I (BB) consists of two B chains, CK-II (MB) consists of one M and one B chain, and CK-III (MM) consists of two M chains. Creatine kinase is found predominantly in skeletal (striated) muscles, heart muscle, and brain tissue. Each organ contains a different proportion of CK isoenzymes. Therefore, when an elevated total CK concentration is detected, additional information can be obtained by determining the specific isoforms of this enzyme.

An increase in total creatine kinase levels is observed in conditions such as myocardial infarction, head injuries, after surgical procedures, crush syndrome (prolonged compression), myopathic damage of various origins, Duchenne muscular dystrophy and other forms of muscular dystrophy, severe intoxications, and hypothyroidism.

From a physiological perspective, the highest CK activity is observed immediately after birth, after which it decreases. It is important to perform creatine kinase testing as soon as possible, as storing serum in a refrigerator reduces CK activity, which may affect test results.