Blood Smear Evaluation

Objective Lenses and Blood Smears

• An oil immersion lens (100x) is used to observe RBCs.

Blood Smear Characteristics

• The density of blood cells on the smear is significant because it affects the clarity of the blood cell morphology.
• A high-power objective lens (50x to 100x) is used to examine the monolayer of a blood smear.
• The body of a blood smear is where the morphology of blood cells is observed.
• Red blood cells (RBCs), white blood cells (WBCs), and platelets are the three cell series examined in a blood smear.

Neutrophil Shifts

• A left shift of neutrophils indicates the most likely condition of infection or inflammation.
• A right shift of neutrophils indicates a delayed or ineffective response to infection.

Toxic Changes

• The presence of toxic changes in neutrophils indicates the most likely condition of severe infection.

Heinz Bodies

• The presence of Heinz bodies indicates the presence of denatured hemoglobin.

Blood Smear Examination

• The recommended systematic approach for observing blood smears involves examining the feathered edge, the monolayer, and the body of the smear.
• The ideal percentage of blood cells touching each other in the monolayer of a blood smear is 10-20%.

Feathered Edge

• The feathered edge of a blood smear is where the highest concentration of WBCs is found.
• The tail of a blood smear is expected to have the feathered edge.

Reasons for Blood Smears

• One reason for looking at blood smears is to examine blood cell morphology.

Test your knowledge on evaluating blood smears and why they are essential in identifying equipment errors and detecting abnormalities that machines may miss. Learn about the significance of different cell types and morphologies, as well as how to interpret differential plots. Take this quiz to enhance your understanding of blood smear evaluation.