Platelet value of 85×10^9/L represents a decrease in platelet value. If this value alone does not determine whether to do a bone puncture, common causes include improper use of drugs, hypersplenism, primary thrombocytopenic purpura, acute leukemia and so on. Consideration should be given to possible primary causes in conjunction with relevant clinical symptoms before deciding whether or not to perform a bone puncture. If leukemia and other conditions are considered, it is required. 1. Inappropriate use of drugs: Usually inappropriate use of some drugs such as sulfa, quinidine, etc., causing thrombocytopenia, do not need bone puncture. 2. Hypersplenism: cause platelets to be retained in the body in large quantities, causing peripheral blood platelet reduction, at this time no need to do bone puncture. 3. Primary thrombocytopenic purpura: the immune intolerance of own platelet antigen, resulting in excessive destruction of platelets and reduced generation, need to do bone puncture. 4. Acute leukemia: abnormal proliferation of leukemia cells, inhibit normal hematopoietic cells, resulting in decreased red blood cells and platelets, need to do bone puncture. There may be other reasons for the decrease of platelet value, it is recommended to go to the hospital in time, improve the examination, clarify the cause of the disease, and carry out standardized treatment under the guidance of the doctor.