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.

Evaluation of serum ferritin as a tumor marker for canine histiocytic sarcoma.

BACKGROUND: Canine histiocytic sarcoma (HS) is an aggressive malignancy. Hyperferritinemia has been documented in dogs with HS and could serve as a tumor marker aiding in diagnosis and treatment. In people, hyperferritinemia is found in inflammatory diseases, liver disease, and hemolysis, and thus may occur in dogs with these conditions. OBJECTIVE: To determine if serum ferritin concentration is a tumor marker for canine HS. ANIMALS: Dogs with HS (18), inflammatory diseases (20), liver disease (24), immune-mediated hemolytic anemia (IMHA) (15), and lymphoma (23). METHODS: Prospective, observational, cohort study: Serum ferritin concentration was measured at initial diagnosis. Parametric methods were used to compare mean log ferritin concentrations among disease categories. Receiver-operating characteristic curves and likelihood ratios were used to evaluate serum ferritin concentration as a tumor marker. RESULTS: Varying proportions of dogs with IMHA (94%), HS (89%), liver disease (79%), lymphoma (65%), and inflammatory diseases (40%) had hyperferritinemia. Dogs with IMHA had significantly higher mean ferritin concentration than dogs in all other categories. Dogs with HS had significantly higher mean ferritin concentration than those in the inflammatory disease and lymphoma categories. Mean serum ferritin concentration was not significantly different between dogs with HS and those with liver disease. Decision thresholds were determined to distinguish IMHA and HS from the other diseases associated with hyperferritinemia. CONCLUSION: Hyperferritinemia is common in dogs with HS and, after IMHA is ruled out, the degree of hyperferritinemia may be useful in differentiating dogs with HS from dogs with inflammatory diseases, liver disease, and lymphoma.