Approach to the Peripheral Blood Smear - Morphology ...

Approach to the Peripheral Blood Smear - Morphology and Pathology

Low power (200x): Scan slide for WBC distribution. Identify the “thick” edge and the “feathered” or thin edge.

Med power (400x): Examine feathered edge for rouleaux, parasites, abnormal WBC, platelet aggregation / microsatellites.

Oil Immersion (1000x): Assess the size, shape, and morphology of major cell lineages:

 • RBC: Examine where RBCs are close but not touching, compare to lymphocyte nucleus size for scale

 • WBC: Concentrate on edges and thin end of film, normal WBC include PMN, eos, basos, lymphocytes, monocytes


 • Hypochromia / microcytes (↓Fe, thal); 

 • Spherocytes (AIHA, HS); 

 • Schistocytes (valve, MAHA); 

 • Target cells (thal, Hb dz, liver dz, asplenia); 

 • Tear drops / nRBCs (myelofibrosis, myelophthisis, thal); 

 • Bite cells / Heinz bodies (G6PD); 

 • basophilic stippling (thal, Pb, sideroblastic); 

 • acanthocytes / echinocytes (liver dz/renal dz); 

 • Howell-Jolly bodies (sickle dz, asplenia)


 • HypOsegmented PMNs (MDS); 

 • hypERsegmented PMNs (folate/B12); 

 • toxic granulation (sepsis); 

 • myeloid vs. lymphoid precursors (left shift, myelocytes, blasts, Auer rods)

 • basophils (MPD)


 • Clumping (pseudothrombocytopenia); 

 • Large platelets (↑ production, ITP, or congenital disease)

#Peripheral #Blood #Smear #Pathology #differential #diagnosis #morphology
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MGH White Book Manual
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