Spherocytes
Morphology: red blood cells with a spherical rather than biconcave shape. Spherocytes appear smaller than normal red blood cells, with loss of central pallor in dogs. Look alike: microcytes (may be… Read more Spherocytes →
Anisocytosis
Morphology: variation in red blood cell size due to the presence of red cells larger than normal (macrocytes and polychromatophils), red cells smaller than normal (microcytes and spherocytes), or both. Commonly… Read more Anisocytosis →
Microcytes
Morphology: red blood cells that are smaller than normal. May be hypochromic or normochromic. Central pallor is preserved (in dogs). Look alike: spherocytes (may be difficult to distinguish spherocytes from microcytes in… Read more Microcytes →
Macrocytes
Morphology: red blood cells that are larger than normal, may be hypochromic or normochromic. Look alike: polychromatophils (also larger than normal but stain dark purple). Commonly seen with: other features of… Read more Macrocytes →
Mast Cells
Morphology: leukocyte with a large round nucleus and numerous dark purple or blue cytoplasmic granules. Usually seen at the feathered edge of blood smear. Considerable variation in appearance of mast… Read more Mast Cells →
Torocytes
Morphology: red blood cells with increased central pallor and a normal thick rim of hemoglobin creating a “punched out” appearance. Look alikes: codocytes (bullseye), hypochromasia (increased central pallor with thin rim of… Read more Torocytes →
Codocytes
Also called: target cells Morphology: canine red blood cells with a bullseye appearance. Caused by increased ratio of cell membrane to hemoglobin content which results in a central bulge. Look alike:… Read more Codocytes →
Polychromatophils
Morphology: immature red blood cells that stain dark purple on Romanowsky stains (Wright’s, Diff-Quick) due to retained cytoplasmic RNA. Larger than normal red cells. Commonly seen with: features of regenerative anemia (macrocytosis,… Read more Polychromatophils →
Cells and Smears 