The fibrinolytic system is the most important anticoagulation system in the body. During lysis, thrombin hydrolyzes fibrin, releasing soluble fibrin monomers, which, under the action of factor xIIIa, form stable cross-linked fibrin. In late stages of disseminated intravascular coagulation, the fibrinolytic system is activated due to intravascular coagulation, resulting in secondary fibrinolysis and more pronounced bleeding symptoms. What are the tests for secondary enhanced fibrinolysis? 1, plasma fisetin paraclotting test Plasma fisetin paraclotting test, also known as 3P test, is a relatively old test to detect fibrin degradation products. Fibrin sulfate can make fibrin monomer and fibrin degradation products in the soluble complex of fibrin monomer dissociation, fibrin degradation products and their own polymerization is visible to the naked eye fibrous, flocculent or jelly-like material, which reflects the presence of fibrin degradation products, according to the occurrence of different types of fibrinolysis, this test can yield different results. 2.Prothrombin time Prothrombin time is a simple test to detect the function of coagulation, anticoagulation and fibrinolytic system. In particular, it can find out whether the fibrin in the plasma contains sufficient amount of fibrinogen and whether the result is normal. Fibrin degradation products Under the action of fibrinolytic enzymes, fibrin (original) can be degraded to produce fragments of different molecular weights X, Y, D, E and some other fragments, which are collectively called fibrin (original) degradation products (FDP). Tests to determine the amount of FDP in plasma (or urine) usually include immunoelectrophoresis, immunodiffusion, flocculent precipitation, latex agglutination (Fi) test, erythrocyte agglutination inhibition test, staphylococcal aggregation test, reverse hemagglutination test, and enzyme-linked immunosorbent assay, among others.