Clinical coagulation four usually refers to the prothrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT) and plasma fibrinogen (FIB), is one of the commonly used clinical tests, mostly to understand whether the test is normal coagulation function, or to prevent hemorrhage during surgery, and the use of antithrombotic drugs affected, such as test results abnormal need to promptly go to the hospital If the test result is abnormal, it is necessary to go to the hospital in time to seek help from professional doctors. The normal values and significance of the four coagulation items are as follows: 1. TT: the normal value is about 12-16s, which mainly reflects the time for fibrinogen to be converted into fibrin. prolonged TT is often due to the hyperfibrinolytic phase of diffuse intravascular coagulation, low (no) fibrinogenemia, and increased fibrin (original) degradation products in the blood. In case of TT shortening, there is usually no special clinical significance; 2. PT: The normal value is about 11-14s, if it exceeds the normal value by 3s, or more is abnormal. PT prolongation is common in some congenital coagulation factor and fibrinogen deficiency, acquired coagulation factor deficiency, such as vitamin deficiency, disseminated intravascular coagulation, severe liver disease. PT shortening is common in blood hypercoagulation state or thrombotic disease, etc.; 3, APTT: normal value is about 25-37s, mainly reflecting the condition of endogenous coagulation system APTT prolongation is usually seen in hemophilia A, hemophilia B, coagulation factor deficiency, etc. APTT shortening is usually seen in hypercoagulable state of blood; 4, FIB: normal value is about 2-4g/L, mainly reflects the content of fibrinogen. Fibrointegrin: The normal value is about 4-4g/L, mainly reflecting the fibrinogen content.