Creatine kinase (CK) is predominantly found in skeletal muscle and smooth muscle and is mainly used in the diagnosis of skeletal muscle disease as well as cardiac muscle disease, with normal values ranging from 18 to 198. Generally creatine kinase is higher than twice the normal value to be clinically significant. Clinical significance of high creatine kinase: 1. It is mainly used for the early diagnosis of acute myocardial infarction. It starts to rise in 2-4 hours at acute onset, reaches a peak in 12-48 hours, and can return to normal in 2-4 days. And the degree of increase is basically consistent with the degree of myocardial damage. After thrombolytic treatment of myocardial infarction restores blood flow to the infarcted vessels, CK reaches peak time earlier, so dynamic detection of CK changes helps in disease observation and prognosis estimation. 2, various muscle diseases, such as progressive myotonic dystrophy episodes, viral myocarditis, polymyositis, severe muscle injury (such as extrusion syndrome) or increased levels of serum CK after surgery. 3. The level of serum CK is increased in cerebrovascular disease, acute traumatic brain injury, alcoholism, generalized convulsions and epileptic seizures; the level of CK is also increased in hypothyroidism with mucinous edema and cerebral infarction. 4. Creatine kinase may increase transiently after surgery, cardiac catheterization, coronary angiography, exercise test, repeated inotropic injection, and strenuous exercise. Creatine kinase is more than 300, and it is difficult to make a specific diagnosis if you simply look at this one indicator. It is one of the cardiac enzymes and needs to be combined with the two indicators of creatine kinase isoenzyme and troponin and whether there is a dynamic evolution. There are many diseases that can lead to creatine kinase elevation, and it is not specific, such as muscle strain, fracture, myocarditis, myocardial infarction, inflammatory infections and hypothyroidism. If creatine kinase is elevated along with creatine kinase isoenzymes and troponin, then the condition is more severe and acute myocardial infarction is highly suspected.