This canine blood smear shows polychromasia, anisocytosis, and spherocytosis. Polychromasia and anisocytosis are evidence of a regenerative anemia, so perform a reticulocyte count to confirm a regenerative response.
Polychromasia is variation in red blood cell (RBC) color; anisocytosis is variation in RBC size.
Spherocytosis typically occurs due to immune-mediated damage to the RBC membrane resulting in a rounded (i.e., spherical) appearance to the RBC. This is seen most commonly in dogs with immune-mediated hemolytic anemia (IMHA), but may occur secondary to blood transfusion, so always interpret with caution.
Reticulocytes are immature RBCs, released early from the bone marrow; use new methylene blue staining to identify these cells. Look for reticulocytosis with regenerative anemia in most species except horses. The reticulocyte count is a measure of the bone marrow response to anemia.
For more info and images, see the Cornell Clin Path website: RBC Morphology and Hematology Atlas.
Image courtesy of Seth Chapman, DVM, MS, DACVP.
