Creatine phosphokinase (CPK) is an enzyme in the body. It is found mainly in the heart, brain, and skeletal muscle. This article discusses the test to measure the amount of CPK in the blood.
How the Test is Performed
A blood sample is needed. This may be taken from a vein. The procedure is called a venipuncture.
This test may be repeated over 2 or 3 days if you are a patient in the hospital.
How to Prepare for the Test
No special preparation is needed most of the time.
Tell your health care provider about any medicines you are taking. Drugs that can increase CPK measurements include amphotericin B, certain anesthetics, statins, fibrates, dexamethasone, alcohol, and cocaine.
How the Test will Feel
You may feel slight pain when the needle is inserted to draw blood. Some people feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
When the total CPK level is very high, it most often means there has been injury or stress to muscle tissue, the heart, or the brain.
Muscle tissue injury is most likely. When a muscle is damaged, CPK leaks into the bloodstream. Finding which specific form of CPK is high helps determine which tissue has been damaged.
Nagaraju K, Lundberg IE. Inflammatory diseases of muscle and other myopathies. In: Firestein GS, Budd RC, Harris ED Jr, et al, eds. Kelley's Textbook of Rheumatology. 9th ed. Philadelphia, PA: Elsevier Saunders; 2012: chap 85.
Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.