The normal value of platelets in normal adults is (100~300)×10⁹/L, and platelets are safe within this range. Platelets are one of the more important components of human blood, the main role is to promote wound hemostasis and accelerate coagulation, when the human body has a wound, platelets will be aggregated at the ruptured blood vessels, forming platelet plugs, while releasing adrenaline and other vasoconstrictive substances to promote blood coagulation. The normal value of platelets in the blood of a normal adult is (100~300)×10⁹/L, too much or too little can lead to disease. Platelets below the normal value are commonly found in thrombocytopenic purpura, aplastic anemia and leukemia, and above the normal value are commonly found in primary thrombocythemia, true erythrocytosis and other diseases. If the platelet index is abnormal, further examination should be conducted under the guidance of a doctor to clarify the cause of the disease and receive standardized treatment.