CPK isoenzymes test
Creatine phosphokinase - isoenzymes; Creatine kinase - isoenzymes; CK - isoenzymes
The CPK isoenzymes test measures the different forms of creatine phosphokinase (CPK) in the blood. CPK is an enzyme found mainly in the heart, brain, and skeletal muscle.
How the Test is Performed
A blood sample is needed. This may be taken from a vein. The test is called a venipuncture .
Venipuncture
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
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 diagnosis 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:
- Alcohol
- Amphotericin B
- Certain anesthetics
- Cocaine
- Fibrate drugs
- Statins
- 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 or only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
This test is done if a CPK test shows that your total CPK level is elevated. CPK isoenzyme testing can help find the exact source of the damaged tissue.
CPK test
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...
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 cancer
A brain tumor is a group (mass) of abnormal cells that start in the brain. This article focuses on primary brain tumors in children.
-
Brain injury
(due to any type of injury including, stroke, or bleeding in the brain)
Brain injury
A head injury is any trauma to the scalp, skull, or brain. The injury may be only a minor bump on the skull or a serious brain injury. Head injury c...
- Electroconvulsive therapy
- Pulmonary infarction
-
Seizure
Seizure
A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain. The term "seizure...
Higher-than-normal CPK-2 levels:
CPK-2 levels rise 3 to 6 hours after a heart attack . If there is no further heart muscle damage, the level peaks at 12 to 24 hours and returns to normal 12 to 48 hours after tissue death.
Heart attack
Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. ...
Increased CPK-2 levels may also be due to:
- Electrical injuries
-
Heart
defibrillation
(purposeful shocking of the heart by medical personnel)
Defibrillation
Cardioversion is a method to return an abnormal heart rhythm back to normal.
- 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:
-
Crush injuries
Crush injuries
A crush injury occurs when force or pressure is put on a body part. This type of injury most often happens when part of the body is squeezed betwee...
-
Muscle damage due to drugs or being immobile for a long time (
rhabdomyolysis
)
Rhabdomyolysis
Rhabdomyolysis is the breakdown of muscle tissue that leads to the release of muscle fiber contents into the blood. These substances are harmful to ...
-
Muscular dystrophy
Muscular dystrophy
Muscular dystrophy is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.
-
Myositis
(skeletal muscle inflammation)
Myositis
Myositis is an inflammation or swelling of the muscles. It is usually caused by injury, infection, medicines, or an autoimmune disorder.
- Receiving many intramuscular injections
- Recent nerve and muscle function testing (electromyography)
- Recent seizures
- Recent surgery
- Strenuous exercise
Considerations
Factors that can affect test results include cardiac catheterization , intramuscular injections, recent surgery, and vigorous and prolonged exercise or immobilization.
Cardiac catheterization
Cardiac catheterization involves passing a thin flexible tube (catheter) into the right or left side of the heart. The catheter is most often insert...
Isoenzyme testing for specific conditions is about 90% accurate.
References
Anderson JL. ST segment elevation acute myocardial infarction and complications of myocardial infarction. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 73.
Chinnery PF. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 429.
Ferri FF. Muscular Dystrophy. In: Ferri FF, ed. Ferri's Clinical Advisor 2016 . Philadelphia, PA: Elsevier Mosby; 2016:pp. 832-833.
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.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 1/9/2015
Reviewed By: 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.