Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Normal

Platelets*


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› 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 [Compare]
• Stain precipitate
• Malaria infection [Compare]
• Babesia infection [Compare]

› 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:


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for direct comparison
› Misc:

• Platelets are the smallest cellular fragments noted on a peripheral blood smear