Figure 4-2a. Variations in erythrocytes: Poikilocytosis: Sickle cells.
(2) Sickle cell (Drepanocytes). Sickle cells are abnormal erythrocytes that
assume a crescent or sickle-shaped appearance under conditions of reduced oxygen
tension. The presence of sickle cells is an inherited abnormality due to the presence of
hemoglobin S. Sickle cell anemia is encountered primarily in Blacks.
Figure 4-2b. Variations in erythrocytes:
(3) Spherocytes. These are abnormal erythrocytes that are spherical in
shape, having a diameter smaller than normal, and a darker stain (without central pallor)
than normal erythrocytes. These cells are found in instances of hemolytic anemias and
are particularly characteristic of congenital hemolytic jaundice, a hereditary disorder.
Figure 4-2c. Variations in erythrocytes:
Anisocytosis and Target Cells.