Creatinine kinase (CK) is an enzyme which is necessary for muscle function and is found in the heart and skeletal muscles as well as other tissues. It signifies muscle cell damage and death and is measured to diagnose and monitor muscle damage. CK levels tend to be higher in people with greater muscle mass.
What might a low result mean?
Low levels of CK can be found in individuals with liver disease, and in those with muscular diseases which deplete their muscle mass.
What might a high result mean?
The level of CK in the blood is measured to assess muscle damage - it can rise rapidly after muscle trauma, but will subside as the damage repairs. If CK continues to rise it indicates that muscle damage is not being repaired. If you have been to the gym the day before your blood test you may well have raised levels of CK.
Several drugs including cholesterol-lowering drugs (statins), have the potential to damage muscle and increase CK levels. Drinking too much alcohol slightly increases CK as well.