Evaluation of Iron Deficiency Using Reticulocyte Indices in Dogs Enrolled in a Blood Donor Program

BACKGROUND People donating blood more than twice annually are at risk of developing iron deficiency. Little is known about the iron status of dogs enrolled in blood donor programs. HYPOTHESIS Dogs donating blood ≥6 times annually will show evidence of iron deficiency based on their reticulocyte indices. ANIMALS Thirteen dogs enrolled in a blood donor program donating ≥6 times over the preceding 12 months and 20 healthy nondonor control dogs. METHODS Prospective observational study. Mature red blood cell (RBC) indices, reticulocyte indices, serum iron, serum ferritin, and total iron-binding capacity (TIBC) were compared between groups. RESULTS Packed cell volume (median 47%, range 40-52%, P < .01), hematocrit (median 46.4%, range 40.3-52.5%, P < .01), and reticulocyte count (median 16,000/μL, range 9,000-38,000/μL, P < .01) were significantly lower in the blood donor dogs. No statistically significant differences were noted in the mature RBC indices between groups. Both reticulocyte mean corpuscular volume (median 88.8 fL, range 83.4-95.5 fL, P = .03) and reticulocyte hemoglobin content (median 24.6 pg, range 23.1-26.6 pg, P < .01) were significantly lower in the blood donor group. Serum iron and ferritin were similar between groups; however, TIBC was significantly higher in the control group (median 403 μg/dL, range 225-493 μg/dL, P = .02). CONCLUSIONS The findings in dogs donating ≥6 times annually suggest the presence of iron-deficient erythropoiesis in this population.