Coagulation four tests are most commonly used clinically for the following diseases: 1, bleeding disorders: such as nosebleeds, bleeding gums in the mouth, skin petechiae or bleeding spots, which can determine whether the patient lacks coagulation factors or disease triggering factors; 2, hemophilia: endogenous factor VIII, factor IX and factor X deficiency can cause hemophilia, factor VIII deficiency mainly causes hemophilia A, factor IX deficiency can cause hemophilia B Hemophilia can be caused by factor VIII deficiency, factor IX deficiency can cause hemophilia B, and factor X deficiency can cause hemophilia C. 3, abnormal liver function: because many coagulation factors in the four coagulation items are secreted in the liver, liver damage can be seen in the abnormal coagulation factors, and the four coagulation results can also be abnormal, which can monitor the degree of hepatitis patients and whether there is a risk of bleeding. 4, DIC: that is, diffuse intravascular coagulation, which is more dangerous. Pregnant women bleeding after delivery, eventually causing DIC, it is difficult to rescue, the degree of danger is relatively high, the need to do the four coagulation tests to simply determine the coagulation situation. Other, taking anticoagulant drugs, this is when you need to monitor the anticoagulation level and determine whether the amount of drugs is appropriate, taking too much drugs can cause the risk of bleeding due to blockage of the clotting mechanism. Organ transplantation will have bleeding, and coagulation tests are needed to determine whether the transplant is successful and whether there are clotting abnormalities.