Evaluating a blood smear

Question 1

Why do we look at blood smears?

Answer 1

To spot equipment errors
Find things that the machines can’t:
○ Bands, metamyelocytes, toxic change
○ nRBC’s, inclusions, parasites
○ Red cell morphology
Spherocytes
Acanthocytes
○ Early red cell regeneration
Polychromatophils

Question 2

How to examine a blood smear

Answer 2

Start at low/medium power
Identify 3 zones
Feathered edge
Platelet clumps
Big cells
Big parasites
Body
Rouleaux
Agglutination
Monolayer
RBC density
WBC numbers
Estimated differential

Medium/high power
○ Platelet numbers and morphology
○ RBC morphology (small parasites)
○ WBC morphology
○ WBC differential count