Erythrocyte microcytosis

From Dog

Microcytosis (decreased mean corpuscular volume: MCV) is a common laboratory finding in certain dog breeds.

Common causes include:

  • Artefactual - prolonged storage at room temperature
  • Physiological - young animals (pups under 12 weeks of age)
  • Breed predisposition - Akita, Shiba[1], Shar Pei, Siberian Husky, dyserythropoietic disorder in English Springer Spaniels
  • Iron deficiency[2] - pyridoxine or copper deficiency, zinc toxicity, chronic external blood loss (e.g. gastrointestinal bleeding), low iron intake, drugs binding (e.g. chloramphenicol)
  • Liver disease - portosystemic shunt[3]

Although iron deficiency may induce microcytosis of erythrocytes, low iron levels in dogs associated with hemorrhage or chronic inflammation may not necessarily show microcytosis[4]


  1. Gookin JL et al (1998) Evaluation of microcytosis in 18 Shibas. J Am Vet Med Assoc 212(8):1258-1259
  2. Steinberg JD & Olver CS (2005) Hematologic and biochemical abnormalities indicating iron deficiency are associated with decreased reticulocyte hemoglobin content (CHr) and reticulocyte volume (rMCV) in dogs. Vet Clin Pathol 34(1):23-27
  3. Goodfellow M et al (2008) Effect of storage on microcytosis observed in dogs with portosystemic vascular anomalies. Res Vet Sci 84(3):490-493
  4. Paltrinieri S et al (2010) Microcytosis does not predict serum iron concentrations in anaemic dogs. Vet J 185(3):341-343