Most platelets are 1.5-3 μm in diameter. Small platelets are less than 1.5 μm in diameter. Large platelets usually range from 4 to 7 μm. Giant platelets are larger than 7 μm and usually 10-20 μm in diameter. Platelets that are larger than the size of the average red cell in the field qualify as giant platelets. Seen in many different reactive, neoplastic, and inherited conditions including myeloproliferative and myelodysplastic disorders, autoimmune thrombocytopenia, in association with severe leukemoid reactions, May-Hegglin anomaly and Bernard-Soulier syndrome.
