COMPARATIVE STUDY OF DIFFERENTIAL LEUKOCYTE COUNTING BY MICROSCOPY AND AUTOMATIC HEMATOLOGICAL ANALYZER

Abstract

The objective of this study was to compare leukocyte differential counts obtained through microscopy with those performed by an automated hematology analyzer. Reports from 71 canine blood samples processed by two methods were analyzed: the ProCyte DX hematology analyzer and microscopy. Values for total leukocytes (TL) and individual leukocyte series from both methods were used. Alerts issued by the analyzer were also analyzed. The samples were divided into two groups: healthy animals and sick animals (further subdivided based on total leukocyte count: leukocytosis, leukopenia, and normal TL). There was a moderate to excellent correlation for most parameters. The results showed similarity between the techniques, except for basophils (in all groups) and neutrophils in the sick/leukocytosis group. In the hematology analyzer, basophil counts were higher than those obtained by microscopy. For neutrophils in the leukocytosis group, the automated count was lower than the microscopy count, inducing a compensatory increase trend in lymphocytes. The hematology analyzer performed well in alerting the presence of immature neutrophils when they exceeded 4% in the blood. It is concluded that the automated analyzer's leukocyte differential count is similar to manual microscopy in dogs with normal TL; however, microscopic review is necessary for morphological evaluation and quantification of immature neutrophils. For dogs with leukocytosis, microscopic differential counting is essential.