This test card is used for quantitative determination of D-dimer in human serum, plasma or whole blood in vitro. D-dimer is a specific degradation product of fibrin monomer crosslinked by activation factor XIII and hydrolyzed by plasmin. It is a specific marker of fibrinolysis process. Among the degradation products of fibrinolytic protein, only D-dimer cross-linked fragments can reflect the thrombolytic activity after thrombosis. The increased level of D-dimer indicates the frequent degradation of fibrin in vivo. D-dimer plays an important role in the diagnosis and treatment of fibrinolytic system diseases (such as DIC, various thrombus) and fibrinolytic system related diseases (such as pregnancy syndrome), as well as thrombolytic therapy monitoring.