CPK同工酶试验

定义

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.

选择的名字

Creatine phosphokinase - isoenzymes; Creatine kinase - isoenzymes; CK - isoenzymes; 心 attack - CPK; Crush - CPK

How the Test is Performed

A blood sample is needed. This may be taken from a vein. 这个测试叫做a 静脉穿刺.

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:

• 酒精
• 两性霉素B
• 某些麻醉药
• 可卡因
• Fibrate药物
• 他汀类药物
• Steroids, such as dexamethasone

This list is not all-inclusive.

考试的感觉如何

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

如果a 肌酸磷酸激酶试验 shows that your total CPK level is elevated. CPK isoenzyme testing can help find the exact source of the damaged tissue.

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:

• 脑癌
• 脑损伤 (due to any type of injury including, stroke, or bleeding in the brain)
• Electroconvulsive therapy
• 肺梗塞
• 癫痫发作

Higher-than-normal CPK-2 levels:

CPK-2 levels rise 3 to 6 hours after a 心脏病. 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.

Increased CPK-2 levels may also be due to:

• 电气伤害
• 心 去纤颤状态 (purposeful shocking of the heart by medical personnel)
• 心 injury (for instance, from a car accident)
• Inflammation of the heart muscle usually due to a virus (myocarditis)
• 心脏直视手术

Higher-than-normal CPK-3 levels are most often a sign of muscle injury or muscle stress. 这可能是由于:

• 挤压伤
• Dermatomyositis or polymyositis
• Muscle damage due to drugs or being immobile for a long time (横纹肌溶解)
• 肌肉萎缩症
• 肌病
• 肌炎 (skeletal muscle inflammation)
• Receiving many intramuscular injections
• Recent nerve and muscle function testing (electromyography)
• 最近的癫痫发作
• 最近的手术
• 横纹肌溶解
• 剧烈运动

注意事项

Factors that can affect test results include 心导管检查, intramuscular injections, recent surgery, and vigorous and prolonged exercise or immobilization.

Isoenzyme testing for specific conditions is about 90% accurate.

参考文献

哈比卜G. 心脏病学. 见:哈佛大学国会议员编. 医学的秘密. 6日艾德. 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. 临床化学. 9日艾德. St Louis, MO: Elsevier; 2021:chap 16.

Panteghini米. 血清酶. In: Rifai N, Chiu RWK, Young I, Burnham CD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7日艾德. St Louis, MO: Elsevier; 2023:chap 32.

Pincus MR, Carty RP. 临床酶学. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 21.