Platelet count is variable. Platelets are derived from bone marrow megakaryocytes and function to stop bleeding, clotting, repairing broken blood vessels, and preventing the continued outflow of blood. Platelet counts are variable, and indicators can be elevated or lowered. 1. Reactive elevation: such as after splenectomy, acute blood loss, acute infection, acute hemolysis or certain cancer patients, platelet count will return to normal after these causes are controlled. 2. Decreased reactivity: when a large amount of stock blood or plasma is imported within a short period of time, the blood is diluted and the platelet count is decreased; when certain blood diseases, such as aplastic anemia, thrombocytopenic purpura, etc., occur, the platelet count is decreased. When there is a platelet count greater than 400×10⁹/L or less than 100×10⁹/L, it is necessary to go to the hospital at the first time to clarify the cause of the disease, and early diagnosis and treatment under the guidance of physicians.