The plasma prothrombin time, a screening test that reflects the exogenous coagulation pathway in the body, has a normal range of 11-13 seconds. Low plasma prothrombin time is commonly seen in patients with high blood clotting, such as hyperlipidemia, cerebral thrombosis, coronary artery disease, and myocardial infarction, all of whom have low plasma prothrombin time, which often means that various thrombotic and embolic diseases have occurred or are likely to occur in the body, and often require identification of the cause of increased blood viscosity and appropriate treatment. If the plasma prothrombin time is low due to severe hyperlipidemia, it is necessary to eat a light diet, drink more water, and take lipid-lowering drugs such as acipimox, which can avoid or reduce the occurrence of thrombotic diseases. In clinical practice, high plasma prothrombin time is a little more common, such as in patients applying warfarin or in rat poisoning.