Images show peripheral blood smears with numerous spherocytes present (examples are indicated by arrows). From MLS Collection, University of Alberta.

Image 1: 100x oil immersion. https://doi.org/10.7939/R39883320

Image 2: 50x oil immersion. https://doi.org/10.7939/R3XG9FS24

Cell Description:

Round red blood cells that lack an area of central pallor. Cells often appear darker and smaller than a normocytic red blood cell.¹

Cell Formation:

Formation of spherocytes in circulation occurs due to a partial loss of the red blood cell membrane. This can occur when RBCs are not fully phagocytosed by macrophages during extravascular hemolysis.² Cellular content remains the same and this leads to a decrease in the surface to volume ratio and spherocyte formation.³

Hereditary Spherocytosis: the formation of spherocytes occurs due to the defects in the vertical protein linkages between the membrane and cytoskeleton, resulting in a loss of unsupported RBC membrane and spherocyte formation.⁴

Associated Disease/Clinical States:^1,5-7

Hereditary Spherocytosis

Warm Auto-Immune Hemolytic Anemia (WAIHA)

Drug-Induced Immune Hemolytic Anemia

Allo-Immune-mediated hemolysis (delayed hemolytic transfusion reactions, Hemolytic Disease of the Fetus and Newborn)

Glucose-6-Phosphate (G6PD) Deficiency

Transfused cells (storage lesion)

Severe burns

Note: Spherocytes have an increased MCHC (>360 g/L).⁵

References:

1. Rodak BF, Carr JH. Variations in shape and distribution of  erythrocytes. In: Clinical hematology atlas. 5th ed. St. Louis, Missouri: Elsevier Inc.; 2017. p. 93-106.

2. Doig K. Introduction to increased destruction of erythrocytes. In: Rodak’s hematology clinical applications and principles.  5th ed. St. Louis, Missouri: Saunders; 2015. p. 348-66.

3. Bain BJ. Morphology of blood cells. In: Blood cells: a practical guide [Internet]. 5th ed. Chichester, UK: John Wiley & Sons, Ltd; 2015 [cited 2018 Jul 10]: 67-185. Available from: http://doi.wiley.com/10.1002/9781118817322

4. Da Costa L, Galimand J, Fenneteau O, Mohandas N. Hereditary spherocytosis, elliptocytosis, and other red cell membrane disorders. Blood Rev [Internet]. 2013[cited 2018 Jul 24];27(4):167–78. Available from: http://www.sciencedirect.com/science/article/pii/S0268960X13000192

5. Landis-Piwowar K, Landis J, Keila P. The complete blood count and peripheral blood smear evaluation. In: Clinical laboratory hematology. 3rd ed. New Jersey:  Pearson; 2015. p. 154-77.

6. Ford J. Red blood cell morphology. Int J Lab Hematol [Internet]. 2013 Mar 9 [cited 2018 Jul 12];35(3):351–7. Available from: https://doi.org/10.1111/ijlh.12082

7. Turgeon ML. Erythrocyte morphology and inclusions.  In: Clinical hematology: theory and procedures. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1999. p. 99-111.