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

Abstract

BackgroundPeople 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.HypothesisDogs donating blood ≥6 times annually will show evidence of iron deficiency based on their reticulocyte indices.AnimalsThirteen dogs enrolled in a blood donor program donating ≥6 times over the preceding 12 months and 20 healthy nondonor control dogs.MethodsProspective observational study. Mature red blood cell (RBC) indices, reticulocyte indices, serum iron, serum ferritin, and total iron‐binding capacity (TIBC) were compared between groups.ResultsPacked 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).ConclusionsThe findings in dogs donating ≥6 times annually suggest the presence of iron‐deficient erythropoiesis in this population.

Evaluation of an intramuscular butorphanol and alfaxalone protocol for feline blood donation: a pilot study

“…Iron-deficient erythropoiesis is common among human blood donors and has also been documented in canine blood donors. 15,16 Iron deficiency in feline blood donors has not yet been documented but is suspected to occur. Enteral or parenteral iron supplementation is recommended for cats and dogs with evidence of iron deficiency and for iron-deficient human blood donors.…”

Bone marrow iron scoring in healthy and clinically ill dogs with and without evidence of iron‐restricted erythropoiesis

“…Reticulocyte size and hemoglobin content can be measured in whole blood by some hematology analyzers. These reticulocyte indices, particularly decreased reticulocyte hemoglobin content (CHr), can be useful for the early detection of iron‐restricted erythropoiesis in a predisposed patient, but they are not as useful for distinguishing the mechanism of iron restriction 2,8–17 . Serum ferritin is expected to be low in absolute iron deficiency but normal to increased with iron sequestration; however, the assay is not widely available and can be difficult to interpret in animals that have both absolute iron deficiency and inflammatory disease 1 .…”

“…These reticulocyte indices, particularly decreased reticulocyte hemoglobin content (CHr), can be useful for the early detection of iron-restricted erythropoiesis in a predisposed patient, but they are not as useful for distinguishing the mechanism of iron restriction. 2,[8][9][10][11][12][13][14][15][16][17] Serum ferritin is expected to be low in absolute iron deficiency but normal to increased with iron sequestration; however, the assay is not widely available and can be difficult to interpret in animals that have both absolute iron deficiency and inflammatory disease. 1 Soluble transferrin receptor measurement may aid in distinguishing causes of iron-restricted erythropoiesis in humans, but a recent study indicated that the assay was not useful in dogs.…”

Comparison of iron staining and scoring methods on canine bone marrow aspirates

“…Iron‐restricted erythropoiesis is defined as inadequate iron delivery to red cell precursors in the bone marrow, which impairs hemoglobin synthesis and can lead to anemia. Iron‐restricted erythropoiesis can be caused by absolute iron deficiency, iron sequestration, and functional iron deficiency 1‐14 . Absolute iron deficiency is a decrease in total body iron, which in dogs is often due to chronic external blood loss, but could also occur in animals fed diets deficient in iron 4,11,13 .…”