RESUMEN
Leukopenia can be associated with the suppression of the bonemarrow by drugs, malignant disease, systemic lupus erythematosus,infections, and agranulocytosis. However some patients withoutapparent disease have leukocyte counts of less than 4.0 x 109/L. Thedifficulty in differential counting is related to the need of results thatare reliable enough for correct clinical interventions. The aim ofthis study was to compare the results of differential white blood cellcounts of leukopenia patients using different methodologies:electronic counting of cells utilizing the principle of impedanceanalysis and laser dissemination (Cell Dyn 3000), direct count underthe microscope of 200 cells in both whole blood and the leukocytelayer (Buffy coat). Eighty-four samples of blood whit leukocyte countsof less than 4.0 x 109/L were analyzed. The results of this studyshowed that by comparing the different leukocyte count methods,both direct and with automation, neutrophils and lymphocytes showedgood correlations (above 95%), eosinophils, basophils andmonocytes showed low correlation, and basophils, for at least twoof the four groups examined, showed a statistically significantdifference (p <0.05). These data suggest that despite of automationproviding more accurate and sensitive results, the technique ofanalyzing concentrated white blood cells in leukopenia patients cangreatly contribute to confirm electronic count flags and in theidentification of false-positive results.