The blood coagulation system in human body is a very large and complicated system, and the body maintains dynamic balance through the participation of four systems: coagulation, fibrinolysis, platelets and endothelium. Thrombotic disease is a kind of disease with hidden onset, sudden onset and high rate of death and disability. Its pathological process involves three major systems: vascular endothelium, coagulation and fibrinolysis. TAT, PIC, TM and t-PAI-C are effective indicators reflecting the early changes of vascular endothelium, coagulation and fibrinolytic system in the body, which are suitable for early diagnosis, risk assessment, therapeutic efficacy evaluation and thrombosis risk screening in healthy people. The plasmin antiplasmin complex (PIC) is a 1:1 combination of plasmin and inhibitor α2 antiplasmin, which is a biomarker that directly reflects the degree of activation of the fibrinolytic system. The half-life of PIC in plasma is about 6 h, and the clinical reference value is <0.8 μg/mL. When PIC>0.8 μg/mL, fibrinolytic system activation and thrombosis are often indicated. In addition, the activation degree of the fibrinolytic system is related to DIC typing, so PIC can also be used for early diagnosis and typing of DIC, as well as monitoring of thrombolytic therapy.