Erythrocyte volume distribution analysis and hematologic changes in dogs with iron deficiency anemia

Hematologic features were characterized in 12 dogs with iron deficiency anemia attributable to chronic external blood loss. Consistent abnormalities in hemograms included moderate to marked reticulocytosis, decreased mean corpuscular volume, and decreased mean corpuscular hemoglobin concentration. Hypoproteinemia occurred in only four of 12 dogs. Consistent blood film findings included hypochromic cells, leptocytosis, and erythrocyte fragmentation. These dogs had significantly decreased serum iron values (p less than 0.001) and percent transferrin saturation values (p less than 0.001) compared with 33 clinically healthy adult dogs. The total iron binding capacity values of these dogs were not significantly different (p greater than 0.5) than those of the healthy dogs. Using erythrocyte volume distribution curves, the percentages of microcytic cells (less than or equal to 45 fl) were determined to range from 20% to 82%. Sequential changes in erythrocyte subpopulations were evaluated in four dogs which received iron therapy. The hematologic response consisted of fairly rapid restoration of packed cell volume by production of normocytes followed by a more gradual replacement of residual microcytes by new normocytes.