Reticulocytosis

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Reticulocytosis is a large number of immature red blood cells in the blood. Anemic dogs’ bone marrow need to replace red blood cells at a faster rate.

This is a normal, regenerative response to blood loss or hemolytic disease (e.g. anemia). With regard to AIHA, reticulocytosis is therefore usually a good thing – your dog is starting to replace the lost/destroyed red blood cells.

Other causes of reticulocytosis include splenic contraction, excitement/exercise, adrenalin & drugs used for chronic renal failure (e.g. erythropoeitin), lung diseases which cause hypoxia & some hereditary diseases. Reticulocytosis is seen & is normal in new born puppies, also late pregnancy.

Important note: Nucleated RBCs are often seen in haemolytic anaemia during regeneration. When high levels of reticulocytes are seen with nucleated RBCs, this can give rise to an error in automatically (machine) processed blood tests, showing a “false” raised WBC count. These nucleated RBCs can be mistaken for WBCs by the machine. A calculation can be done to obtain a more accurate WBC figure or a manual count could be done in this instance.