Prothrombin is a substance that belongs to the pre-activation phase of thrombin, and testing for prothrombin after a meal generally has no effect. Plasminogen is generally unaffected by eating or fasting and can be tested after eating or fasting. Diagnostic results are not affected by eating, so prothrombin can be tested after a meal. The purpose of checking prothrombin is to understand the condition of coagulation, to determine whether there is any coagulation abnormality according to the time and activity of prothrombin, and to exclude diseases such as hepatocellular necrosis, coagulation dysfunction disease, disseminated intravascular coagulation, and so on. Before checking the prothrombinogen, it should be noted that the diet should be as light and nutritious as possible. It is forbidden to take anticoagulants and antiplatelet aggregation drugs on the first day of the examination, otherwise it will affect the diagnostic result of prothrombinogen.