Platelet count of 345×10⁹/L belongs to mild elevation and still needs regular observation. 1. Platelet count is a general blood test, and its normal value ranges from (100~300)×10⁹/L. If the result is more than 300×10⁹/L, it is called thrombocytosis, and if the result is less than 100×10⁹/L, it is called thrombocytopenia. 2. Increased platelet count can be seen after acute hemorrhage, hemolysis and splenectomy and other reactive increase, but also seen in primary thrombocythemia, chronic granulocytic leukemia and other primary increase. 3. Decreased platelet count can be seen in aplastic anemia, acute leukemia and other generative disorders, as well as in primary thrombocytopenic purpura and hypersplenism. It is recommended to have regular checkups, and if abnormalities occur, consult the doctor in time for treatment under the guidance of the physician.