Hematology Red Flags: The Value of Blood Smear Examination in Horses

Tracy Stokol1

  • 1Department of Population Medicine and Diagnostic Sciences, Cornell University, College of Veterinary Medicine, S1-058 Schurman Hall, Upper Tower Road, Ithaca, NY 14853-6401, USA.

This article uses a case-based approach, complemented with diagnostic algorithms and images, to highlight hematologic changes of pathologic relevance in horses, namely, marked erythrocytosis, anemia or leukocytosis, inflammatory leukograms, lymphocytosis in adult horses, thrombocytopenia, and pancytopenia. These hematologic abnormalities occur with certain diseases and their identification can help clinicians narrow to down differential diagnostic lists. This article highlights the importance of blood smear examination, particularly, but not only, when numerical red flags are identified on automated blood counts.