Why is platelet input necessary? It is mainly for the purpose of hemostasis or prevention of bleeding. Platelets are mainly responsible for hemostasis in the body, forming platelet thrombi by direct adhesion and aggregation, and also promoting coagulation, thus forming firm thrombi. The normal value of platelets is (100-300)×10^9/L. Clinically, we often encounter various cases of platelet reduction. If the platelets are severely reduced, less than 20×10^9/L or there is a bleeding tendency, and surgery is urgently needed, in this case, the platelet count needs to be raised quickly, and platelet transfusion is the most direct and effective method, and it is not expensive. Platelet transfusion is also a blood transfusion, and there are also certain risks, therefore, platelet transfusion must be strictly controlled by the indications.