The clinical reference value is less than 0.05 ng/ml in most cases, because of the different testing reagents used in each hospital. In most cases, the clinical reference value is less than 0.05 ng/ml. The specific reference value is recommended to be based on the reference value given by the hospital where the test was performed. Ultrasensitive troponin I is a regulatory protein of myocardial muscle contraction. After myocardial cell injury, ultrasensitive troponin will be significantly elevated, and its concentration in the blood is relatively high and lasts for a long time. In clinical practice, if patients have obvious symptoms such as chest pain and chest tightness, combined with the data of elevated ultrasensitive troponin I, it can be diagnosed early for angina pectoris and myocardial infarction and other diseases, and play a guiding role in clinical treatment.