Abstract

Hematologic evaluation provides valuable information for diagnosis, treatment, monitoring, and prognosis of the individual patient, and for health assessment of animal populations. Differences in mammalian and non-mammalian species extend from basic anatomy and physiology to morphologic and functional features of blood cells.^1,2 A major difference is the presence of nucleated erythrocytes and thrombocytes in non-mammalian species. As automated hematology analyzers are programmed to consider all nucleated cells as white blood cells, hematologic analysis of non-mammalian blood relies on manual methods. Accurate interpretation of hemogram results requires knowledge and expertise in sample collection, handling, and analysis, as well as species- (or strain)-specific variations in blood cell morphology and pathophysiologic responses. Understanding of the hematology of non-domestic species is continuously expanding, and laboratory reference intervals are being defined for an increasing number of exotic species.

If population-based reference intervals are not available for a given species, subject-based reference intervals can be helpful in the evaluation during treatment and/or monitoring of the individual patient.³ The objective of this overview is to highlight major differences in morphology, function, and physiologic and pathologic blood cell responses across various taxa of mammalian and non-mammalian vertebrate species, and to summarize important factors that should be considered when interpreting hemogram results.

Literature Cited

1.  Harvey JW. Veterinary Hematology: A Diagnostic Guide and Color Atlas. 1st ed. St. Louis, MO: Saunders; 2012.

2.  Campbell TW, Ellis CK. Avian and Exotic Animal Hematology & Cytology. 3^rd ed. Hoboken, NJ: Wiley Blackwell; 2007.

3.  Walton RM. Subject-based reference values: biological variation, individuality, and reference change values. Vet Clin Pathol. 2012;41(2):175–181.