Clinically, high D-dimer is indicative of thrombus formation, and detection of D-dimer is mainly used to exclude thrombus formation in large vessels, reflecting enhanced secondary fibrinolysis, which is a molecular marker of hypercoagulable state and hyperfibrinolysis in vivo. Therefore, reducing the elevated D-dimer requires the application of anticoagulant drugs such as low molecular heparin and warfarin to improve the hypercoagulable state of the blood. If thrombotic diseases such as pulmonary embolism, cerebral infarction, myocardial infarction or deep vein thrombosis have occurred, appropriate thrombolytic therapy is required. Some diseases such as malignant tumor, sepsis, hyperemesis, liver injury disease, leukemia, DIC, etc. can cause the elevation of this index, and then the primary disease needs to be treated actively. The purpose of treatment is not to lower the D-dimer, but to correct the coagulation abnormality, and if the body recovers after treatment, then the D-dimer will naturally decrease to the normal range.