A high prothrombin time on examination suggests the presence of coagulation dysfunction, which may be related to medication (anticoagulant drugs), anemia from liver disease, thrombocytopenia, and coagulation factor deficiency. High prothrombin time, i.e. prolonged prothrombin time, is mainly seen in patients with congenital or acquired coagulation factor deficiency, such as coagulation factor X and fibrinogen deficiency, severe liver disease, hemophilia, etc. It may also be due to drug damage to hepatocytes or other causes of coagulation dysfunction, and can also be seen in patients with anemia and thrombocytopenia. However, prolonged prothrombin time alone cannot diagnose the above-mentioned diseases, and a series of test results, such as clinical symptoms, biochemical tests and routine blood tests, are needed to determine what causes it. Patients with prolonged prothrombin time are at risk of bleeding and should pay attention to the prevention of bleeding in clinical and daily life, and promptly seek medical consultation and supplementation of coagulation factors in case of incessant blood flow.