Also known as: CK, CPK, Creatine Phosphokinase, Total, Serum.

Creatine kinase is an enzyme found in the brain, heart, skeletal muscle, and other tissues. Enzymes such as creatine kinase are proteins that help cells to perform their normal functions. In heart and muscle cells, most of this energy is used when muscles contract. There are three different forms of CK in your body, referred to as isoenzymes:CK-MB (found mostly in your heart); CK-MM (found in your skeletal muscles and heart); CK-BB (found mostly in your brain). The small amount of CK normally in the blood comes mainly from the muscles. The CK in the brain almost never gets into the blood.