CPK isoenzymes test
Creatine phosphokinase - isoenzymes; Creatine kinase - isoenzymes; CK - isoenzymes; Heart attack - CPK; Crush - CPKThe 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.
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.
Read Article Now Book Mark ArticleIf 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:
- 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 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...
Read Article Now Book Mark ArticleCPK 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:
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Brain cancer
Brain cancer
A brain tumor is a group (mass) of abnormal cells that grow in the brain. This article focuses on primary brain tumors in children.
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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. Head injury can be either closed or open (penetrating). A closed head injury means you rec...
Read Article Now Book Mark Article - Electroconvulsive therapy
- Pulmonary infarction
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Seizure
Seizure
A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...
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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. ...
Read Article Now Book Mark ArticleIncreased 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 bring an abnormal heart rhythm back to normal.
Read Article Now Book Mark Article - 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:
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Crush injuries
Crush injuries
A crush injury occurs when excessive force or pressure is put on a body part. This type of injury most often happens when part of the body is squeez...
Read Article Now Book Mark Article - Dermatomyositis or polymyositis
- 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 ...
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Muscular dystrophy
Muscular dystrophy
Muscular dystrophy (MD) is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.
Read Article Now Book Mark Article - Myopathy
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Myositis (skeletal muscle inflammation)
Myositis
Myositis is an inflammation or swelling of the muscles. It is most often caused by injury, infection, medicines, or an autoimmune disorder. Dermatom...
Read Article Now Book Mark Article - Receiving many intramuscular injections
- Recent nerve and muscle function testing (electromyography)
- Recent seizures
- Recent surgery
- Rhabdomyolysis
- 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...
Read Article Now Book Mark ArticleIsoenzyme testing for specific conditions is about 90% accurate.
References
Habib G. Cardiology. In: Harward MP, ed. Medical Secrets. 6th ed. Philadelphia, PA: Elsevier; 2019:chap 4.
Marshall WJ, Lapsley M, Day A, Shipman K. Plasma proteins and enzymes. In: Marshall WJ, Lapsley M, Day A, Shipman K, eds. Clinical Chemistry. 9th ed. St Louis, MO: Elsevier; 2021:chap 16.
Panteghini M. Serum enzymes. In: Rifai N, Chiu RWK, Young I, Burnham CD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 32.
Pincus MR, Carty RP. Clinical enzymology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 21.
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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
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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
Review Date: 1/1/2023
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 C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.