Dimers are specific degradation products of fibrin in the blood after activation and hydrolysis, and are markers of the presence of hypercoagulability and secondary hyperfibrinolysis in the body. The concentration of dimers has a positive significance in the diagnosis of thrombotic diseases, the assessment of therapeutic efficacy and the determination of prognosis. Clinically, secondary hyperfibrinolysis is the main cause of increased dimerization, and common diseases include diffuse intravascular coagulation, organ transplant rejection, myocardial infarction, cerebral embolism, pulmonary embolism, venous thrombosis, surgery, neoplasia, various infections, and tissue necrosis.