Creatine Phosphokinase Definition

Creatine phosphokinase is an enzyme found in the heart, brain, and skeletal muscle, and elevated levels can indicate an injury to one of these tissues. In general, high CPK levels in the muscle suggest the presence of inflammatory muscle disease, but they can also be caused by trauma, injection into the muscle, or muscle disease due to hypothyroidism.

Conversely, low levels of CPK can be indicative of rheumatoid arthritis.