A creatine kinase of 502 U/L is serious and indicates that the heart or skeletal muscle may be substantially damaged. Creatine kinase (CPK) is an enzyme involved in energy metabolism and is found mainly in cardiac muscle, skeletal muscle, and brain. It is used clinically to diagnose myocardial infarction. Creatine kinase phosphate is elevated in the blood 3 to 8 hours after the onset of myocardial infarction in persons with myocardial infarction, predating the changes in serum glutamine aminotransferase and lactate dehydrogenase. Normal values for creatine kinase range from 50 to 310 U/L in men and 40 to 200 U/L in women (rate method), and if creatine kinase reaches 502 U/L. Its clinical significance may be acute myocardial infarction, viral myocarditis, progressive myotonic dystrophy, polymyositis, and in muscle injury, severe angina pectoris, pericarditis, atrial fibrillation, cerebral vascular accidents, meningitis, and cardiac surgery, etc., which need to be analyzed specifically in relation to the patient’s specific disease. Elevated creatine kinase requires prompt medical attention and treatment in conjunction with other tests to clarify the diagnosis.