cTnI refers to ultrasensitive troponin. The normal value of ultrasensitive troponin, which varies slightly from hospital to hospital, should be less than 0.04 ng/ml in most hospitals. cTnI should not exceed 0.04 ng/ml regardless of whether the patient is male or female, infant or elderly, and if it exceeds three times more, that is, if troponin exceeds 0.12 mg/ml. Consider acute cardiomyocyte damage. Acute myocardial cell damage is not necessarily an acute myocardial infarction, but should be determined by the cardiologist, taking into account the patient’s complaints, past medical history, and the course of the disease. This is because some patients can also have acute myocardial marker elevations due to myocarditis, pericardial effusion, tumors, renal insufficiency, severe infections, or even cerebral infarction, and such elevations are low-level elevations. If a patient has elevated myoglobin, creatine kinase, and creatine kinase isoenzyme in addition to elevated ultrasensitive troponin cTnI, the cardiologist can diagnose acute coronary syndrome after making a judgment and combining it with electrocardiogram and other indicators.