Congenital factor X deficiency: This disease is extremely rare, is autosomal recessive, is often inherited by inbred parents, and can develop in both sexes. Because factor X can involve the function of both intrinsic and extrinsic coagulation systems, it can also have similar symptoms to factor VII deficiency, and the degree of bleeding is related to the concentration of factor X. The heterozygous type generally has bleeding symptoms, while the heterozygous type can have no bleeding tendency with factor X concentrations between approximately 20% and 50%. Laboratory tests, prothrombin time (PT), partial thromboplastin time (PTT) and snake venom time are prolonged, the latter can be differentiated from factor VII deficiency. Treatment is based on factor X supplementation, using stored plasma, PPSB or a concentrated preparation of factor X. 10-15 ml of plasma per kg of body weight is infused. The effective hemostatic concentration of factor X is about 5% to 10%. The hemostatic concentration for severe bleeding is about 15% to 20%. How to effectively prevent congenital factor X deficiency? (i) Treatment Replacement therapy is the main treatment for the bleeding symptoms of this disease. Generally minor bleeding does not require treatment. The half-life of FⅪ is about 52h, therefore, one infusion every other day can maintain the plasma level, and the diffusion rate of FⅪ is low, so it is easy to raise the plasma level. There is no concentrated FⅪ preparation in China, fresh plasma or fresh frozen plasma can be used, and supernatant plasma with cold precipitation removed can also be used. Blood bank whole blood loses about 80% of FⅪ in 1 week, so it is not applicable. Generally, 5-20 ml of plasma per kg of body weight can increase the FⅪ level to 25%-50% and achieve an effective hemostasis level. The exact FⅪ level required for normal hemostasis in surgical procedures is not known, and it is generally believed that it should be at or above 50%. This level can be achieved with a preoperative infusion of 30 ml/kg of fresh plasma. After surgery, 5 ml/kg/day or 10 ml/kg fresh plasma every other day until the wound heals. Concentrated FⅪ preparations are available abroad. The main complications of treatment are hepatitis and other transfusion-related viral infections such as HIV. In cases of severe bleeding after transfusion of blood products with FⅪ inhibitors (homologous antibodies), plasma replacement therapy is ineffective in stopping bleeding, and may be effective with activated prothrombin complexes. (B) Prognosis 1. The bleeding is usually mild and the mortality rate due to bleeding is very low. The prognosis depends on the severity of bleeding and complications of substitution therapy in cases with mild bleeding. 2. Patients with severe deficiency of F X may have chronic joint disease similar to hemophilia A and hemophilia B. Repeated infusions of plasma and clotting factor concentrates have infected some patients with hepatitis B or C, which in turn leads to chronic liver disease. 3. The concentrated preparations applied have the risk of inducing thrombosis and DIC.