CPK isoenzymes

Alternative names:

CK - isoenzymes; creatine kinase - isoenzymes; creatine phosphokinase - isoenzymes

What the risks are:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations:

Factors that can affect test results include cardiac catheterization, intramuscular injections, recent surgery, and vigorous and prolonged exercise.

Drugs that can increase CPK measurements include amphotericin B, ampicillin, some anesthetics, anticoagulants, aspirin, clofibrate, dexamethasone, furosemide and morphine.

The total CPK test is about 70% accurate because there are many causes of elevated levels. Isoenzyme testing for individual types of CPK is about 90% accurate.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.