F2 and congenital afibrinogenemia: In terms of blood coagulation function, plasma prothrombin time mainly reflects the function of exogenous coagulation system, and its prolongation is mainly seen in congenital decrease of coagulation factor and fibrinogen deficiency [28]; activated partial thrombin time is mainly the examination index of endogenous coagulation factor deficiency, and its prolongation is common in hemophilia hepatopathy, DIC, and so on [29]; prolonged plasma thrombin time is common in patients with hypofibrinogenemia and abnormal fibrinemia [30].