In general, the normal value of antithrombin 3 is 230-350 mg/L. 1. Antithrombin 3 is an inhibitor of thrombin and coagulation factors D.E.A., Ⅺα, IX.A., X.A. and other serine-containing proteases, and its main function is to exert effective anticoagulant effect to ensure that blood in human body won’t form thrombus, and at the same time won’t form bleeding phenomena. 2. Pathological increase of antithrombin 3: It indicates that the anticoagulant activity of blood is enhanced, which is mainly seen in oral anticoagulant drugs and acute bleeding period. 3. Pathological decrease of antithrombin 3: congenital AT-III deficiency. Blood anticoagulation is weakened in pre-thrombotic state and thrombotic diseases, such as hypercoagulable stage of DIC, myocardial infarction, angina pectoris, cerebrovascular lesions, pregnancy, deep vein thrombosis, nephrotic syndrome, etc.; synthesized is reduced, such as severe liver disease. If patients have symptoms of abnormal antithrombin 3 values, they should go to regular hospitals in time and receive symptomatic treatment under the guidance of professional doctors to avoid delays.