Estudo comparativo da contagem diferencial de leucócitos por microscopia e por analisador hematológico automático

Abstract

The complete blood count (CBC) is a laboratory test that evaluates red blood cells, white blood cells, and platelets in the blood. Nowadays, automated counters are widely used for this test, providing highly accurate results. However, cytological analysis by a trained professional remains necessary to confirm these results and to identify potential cellular abnormalities. The aim of this study was to comparatively analyze the differential leukocyte count obtained via microscopy with that performed by an automatic hematology analyzer. For this purpose, 71 canine CBCs were included, with no specific inclusion criteria, provided they were performed using the ProCyte DX hematology analyzer. Total leukocyte (TL) counts and individual leukocyte subsets, as provided by the device and from manual counts using an optical microscope, were utilized. The animals were divided into two groups: healthy and sick. The latter group was further subdivided into three categories based on total leukocyte counts: leukocytosis, leukopenia, and normal TL. The results from both methods of differential leukocyte counting were analyzed using the Mann-Whitney test or t-test, with a significance level of p<0.05, and by Spearman’s correlation test. A positive correlation ranging from good to excellent was observed for most parameters. The results demonstrated similarity between the two techniques for most parameters, except for the basophil count (in all groups) and the neutrophil count in the sick/leukocytosis group, where a significant difference was found. Basophil counts were higher in all groups when analyzed by the hematology analyzer. In the leukocytosis group, the automated counts for band and segmented neutrophils were lower than those obtained via microscopy, leading to a compensatory increase in lymphocyte values. It was concluded that the differential leukocyte count obtained by the automatic analyzer is similar to the manual count under optical microscopy in dogs with normal total leukocyte counts. However, microscopic verification remains essential, particularly for detecting morphological changes. In dogs with leukocytosis, microscopic differential counts are indispensable.