Hypochromic RBC
Blood film from a dog with chronic blood loss resulting in iron deficiency anemia. Note that, in addition to the hypochromic cells (with increased areas of central pallor), a variety of other shape abnormalities are present (keratocytes, schistocytes).
Hypochromasia is a term with two common usages. As a descriptor of erythroid cells as seen on a blood film, it refers to the appearance of increased central pallor with a thin rim of cytoplasm. For all practical purposes, true hypochromasia in common domestic animal species occurs only in the context of chronic iron deficiency anemia. It is recognized most frequently in dogs.
      The other application of this term is to denote an MCHC below reference range. Hypochromasia in this sense does not necessarily correlate with the appearance of increased central pallor in a smear. In developing iron deficiency anemia, the appearance of hypochromasia in smears precedes the subnormal MCHC.
      Hypochromasia in advanced Fe lack is accompanied by red cell shape abnormalities suggesting fragmentation (schistocytes, keratocytes, eccentrocytes). This may result from diminished deformability of the iron deficient cells.