The normal range of platelets is (100-300) × 10^9 / L, with a wide range of daily physiological fluctuations. 1, platelet test clinical significance of thrombocytosis, when the platelet count > 400 × 10^9 / L is thrombocytosis, common in primary thrombocytosis, mainly due to myeloproliferative diseases, common in myeloproliferative diseases, such as chronic granulocytic leukemia, the True erythrocytosis, primary thrombocytosis, etc. The situation will improve after treatment, and the platelet count will soon drop to normal levels; 2. When the platelet count <100×10^9 units/L is thrombocytopenia, which is common in platelet production disorders, such as aplastic anemia, acute leukemia anemia, etc., and increased platelet destruction, such as thrombocytopenic purpura, hypersplenism, etc., also cause thrombocytopenia, and excessive depletion such as diffuse intravascular coagulation, which can also lead to thrombocytopenia.