An intracellular enzyme which performs an energy function in the body. It is found in large quantities in muscles, a little less in the brain. In this regard, there are 2 subtypes of the enzyme: brain and cardiac.

As the enzyme is contained within cells, its increase in blood indicates the destruction of these cells.

The analysis has become widespread in the diagnosis of myocardial infarction as creatine kinase is detected in the serum in 2-4 hours after the onset of the disease. The peak is reached 24-36 hours and is 5-20 times higher than the norm. CPK can be called one of the first markers of myocardial infarction.

However, increased CPK levels do not only indicate myocardial infarction. It may also be caused by myocarditis and myositis (muscle inflammation), traumatic injuries of the skeletal musculature.

High creatine kinase activity is observed in diseases of the nervous system:

• schizophrenia,
• manic-depressive syndrome,
• diseases caused by psychotropic drugs.

Increased activity of the thyroid gland reduces the CPK level, decreased activity increases the CPK level.

Alcohol and hormones (prednisolone) increase blood serum creatine kinase levels.