A high platelet distribution width indicates a high degree of platelet size dispersion, which is commonly seen in megaloblastic anemia, acute myeloid leukemia, and splenectomy, but can also be seen in other conditions such as chronic granulocytic leukemia, thrombophilia, and giant platelet syndrome. High platelet distribution width indicates a high degree of discrete platelet volume size, i.e., some platelets are large and some are small. 1. If the platelet distribution width is high and huge platelets are seen on blood smear, it can be seen in megaloblastic anemia; 2. If high platelet distribution width is combined with thrombocytopenia and naïve cells are seen on blood smear, it can be seen in acute myeloid leukemia; 3. If the platelet distribution width is high and platelets are elevated, it can be seen in the blood routine manifestations such as after splenectomy; 4. Increased platelet distribution width can also be seen in chronic granulocytic leukemia, thrombophilia, giant platelet syndrome and so on. It is recommended that patients with abnormalities of this index should consult a doctor as soon as possible to identify the cause of the disease under the guidance of a physician.