Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Normal Platelets* Click Here for Full Size › Microscopic Features: Most are 1/5 to 1/3 the size of a normal RBC They are typically round with a blue-gray cytoplasm Cytoplasm with purple/blue granules › Normal % blood-PB, marrow-BM, lymphoid tissue-LN: PB: Many BM: Scattered LN: None › May Resemble: Schistocyte Stain precipitate Malaria infection Babesia infection › Differential Diagnoses: Increased in: Iron deficiency Anemia Acute or chronic inflammation Myeloproliferative Neoplasm (e.g. Essential Thrombocythemia, etc.) Drug reaction Exercise ________________________________________________ Decreased in: Microangiopathic Hemolytic Anemias (e.g. DIC, TTP, and HUS) Malignancy with Marrow infiltration Drug induced Infection (e.g. sepsis leading to DIC) Autoimmune (e.g. ITP) Nutritional deficiencies Splenic sequestration Hereditary › Classic Immunophenotype: CD41+ CD42+ CD61+ › Cartoon Image: Click and drag for direct comparison › Misc: Platelets are the smallest cellular fragments noted on a peripheral blood smear