The creatine phosphokinase (CPK) isoenzymes test measures the different forms of CPK in the blood. CPK is an enzyme found mainly in the heart, brain, and skeletal muscle.
Creatine phosphokinase - isoenzymes; Creatine kinase - isoenzymes; CK - isoenzymes; Heart attack - CPK; Crush - CPK
How the Test is Performed
A blood sample is needed. This may be taken from a vein. The test is called a
If you are in the hospital, this test may be repeated over 2 or 3 days. A significant rise or fall in the total CPK or CPK isoenzymes can help your health care provider diagnose certain conditions.
How to Prepare for the Test
No special preparation is needed in most cases.
Tell your provider about all the medicines you are taking. Some drugs can interfere with test results. Drugs that can increase CPK measurements include the following:
- Amphotericin B
- Certain anesthetics
- Fibrate drugs
- Steroids, such as dexamethasone
This list is not all-inclusive.
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
This test is done if a
CPK is made of three slightly different substances:
- CPK-1 (also called CPK-BB) is found mostly in the brain and lungs
- CPK-2 (also called CPK-MB) is found mostly in the heart
- CPK-3 (also called CPK-MM) is found mostly in skeletal muscle
What Abnormal Results Mean
Higher-than-normal CPK-1 levels:
Because CPK-1 is found mostly in the brain and lungs, injury to either of these areas can increase CPK-1 levels. Increased CPK-1 levels may be due to:
Brain cancer Brain injury(due to any type of injury including, stroke, or bleeding in the brain)
- Electroconvulsive therapy
- Pulmonary infarction
Higher-than-normal CPK-2 levels:
CPK-2 levels rise 3 to 6 hours after a
Increased CPK-2 levels may also be due to:
- Electrical injuries
defibrillation(purposeful shocking of the heart by medical personnel)
- Heart injury (for instance, from a car accident)
- Inflammation of the heart muscle usually due to a virus (myocarditis)
- Open heart surgery
Higher-than-normal CPK-3 levels are most often a sign of muscle injury or muscle stress. They may be due to:
- Muscle damage due to drugs or being immobile for a long time (
rhabdomyolysis) Muscular dystrophy Myositis(skeletal muscle inflammation)
- Receiving many intramuscular injections
- Recent nerve and muscle function testing (electromyography)
- Recent seizures
- Recent surgery
- Strenuous exercise
Factors that can affect test results include
Isoenzyme testing for specific conditions is about 90% accurate.
Anderson JL. St segment elevation acute myocardial infarction and complications of myocardial infarction. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 73.
Marshall WJ, Day A, Lapsley M. Plasma proteins and enzymes. In: Marshall WJ, Day A, Lapsley M, eds. Clinical Chemistry. 8th ed. Philadelphia, PA: Elsevier; 2017:chap 16.
Nagaraju K, Gladue HS, Lundberg IE. Inflammatory diseases of muscle and other myopathies. In: Firestein GS, Budd RC, Gabriel SE, McInnes IB, O'Dell JR, eds. Kelley and Firestein's Textbook of Rheumatology. 10th ed. Philadelphia, PA: Elsevier Saunders; 2017:chap 85.
Selcen D. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 421.
Review Date: 28/01/2019
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