Correlation of Red Blood Cell Morphology with Serum Cobalamin and Folate Concentration in Dogs with Chronic Diarrhea: A Retrospective Study

<b>Background/Objectives</b>: Chronic diarrhea in dogs is a prevalent condition that significantly impacts canine health, often leading to weight loss, dehydration, and malnutrition. Diagnosing and treating chronic diarrhea is challenging due to its multifactorial nature, necessitating collaboration among veterinarians across various specialties. Measuring cobalamin and folate levels is a crucial diagnostic step for all dogs with chronic diarrhea. The role of these vitamins in erythropoiesis is well-documented in human medicine, where deficiencies are linked to erythropoietic disorders and megaloblastic anemia. This study explores the relationship between cobalamin and folate concentrations with hematologic parameters in dogs with chronic diarrhea to develop novel diagnostic methods that facilitate timely decision making. <b>Methods</b>: Forty-seven adult dogs with a history of chronic diarrhea (2019-2023) were included in the study. Upon presentation, complete blood count and measurement of cobalamin and folate concentrations were performed. The correlation of cobalamin and folate levels with erythrocytic parameters, including hematocrit (HCT), hemoglobin concentration (HGB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW), and reticulocyte count, as well as morphological changes in the blood smear were examined. <b>Results</b>: Serum cobalamin was significantly correlated with RBC (<i>p</i> = 0.032), HGB (<i>p</i> = 0.006), HCT (<i>p</i> = 0.005), and MCV (<i>p</i> = 0.022). Anisocytosis was significantly correlated with hypocobalaminemia (<i>p</i> = 0.002), while acanthocytosis correlated with normal cobalamin levels (<i>p</i> = 0.046). No correlation was found between serum folate and erythrocytic parameters or morphological changes. <b>Conclusions</b>: These findings emphasize cobalamin's potential role in canine erythropoiesis, highlighting the need for routine evaluation and supplementation when necessary. Conversely, the lack of association with folate suggests it plays a less significant role in this species. These results underscore the importance of complete blood count in the diagnostic investigation of dogs with chronic diarrhea.