Canine reference intervals for the Sysmex XT-2000iV hematology analyzer

The laser-based Sysmex XT-2000iV hematology analyzer is increasingly used in veterinary clinical pathology laboratories, and instrument-specific reference intervals for dogs are not available.

The purpose of this study was to establish canine hematologic reference intervals according to International Federation of Clinical Chemistry and Clinical and Laboratory Standards Institute guidelines using the Sysmex XT-2000iV hematology analyzer.

Blood samples from 132 healthy purebred dogs from France, selected to represent the most prevalent canine breeds in France, were analyzed. Blood smears were scored for platelet (PLT) aggregates. Reference intervals were established using the nonparametric method. PLT and RBC counts obtained by impedance and optical methods were compared. Effects of sex and age on reference intervals were determined.

The correlation between impedance (I) and optical (O) measurements of RBC and PLT counts was excellent (Pearson r=.99 and .98, respectively); however, there were significant differences between the 2 methods (Student's paired t-test, P<.0001). Differences between sexes were not significant except for HCT, PLT-I, and PLT-O. WBC, lymphocyte, and neutrophil counts decreased significantly with age (ANOVA, P<.05). Median eosinophil counts were higher in Brittany Spaniels (1.87 × 10(9) /L), Rottweilers (1.41 × 10(9) /L), and German Shepherd dogs (1.38 × 10(9) /L) than in the overall population (0.9 × 10(9) /L). PLT aggregates were responsible for lower PLT counts by the impedance, but not the optical, method.

Reference intervals for hematologic analytes and indices were determined under controlled preanalytical and analytical conditions for a well-characterized population of dogs according to international recommendations.