A normal creatine phosphokinase value is 10 to 120 micrograms per liter, according to MedlinePlus. Drugs such as anesthetics, cocaine and alcohol potentially affect this measurement. The range also sometimes differs between laboratories, so it is important to discuss the meaning of specific test results with a health care professional.
Creatine phosphokinase is an enzyme found mainly in the heart, the brain and skeletal muscle, reports MedlinePlus. Doctors test for total CPK levels to determine if injury or stress has occurred in these tissues. They use this test to evaluate the cause of chest pain, diagnose heart attack, detect the presence of various muscle diseases, or make a determination between malignant hyperthermia and postoperative infection.