Benefits of routine automatic blood picture differentiation

: The benefits of automated blood smear differential cell counting as a supplementary laboratory examination have been studied. The investigations focussed on patients of whom hematology requisitions were limited to total leukocyte count and hemoglobin determination. The specimens were derived from patients of departments of surgery and obstetrics and gynecology. For specimen collection the vacutainer system was used. The blood smears were prepared in a Coulter Electronics slide spinner, stained with a Hematek II slide stainer and analyzed in the Coulter Electronics Diff 3-50 cell classifier. A total of 1700 blood smears were examined. Following processing of each sample, the classification of each cell was inspected. Corrections were performed, if necessary, and the number of classification changes performed for each smear was registered. Using the in-house normal ranges, 34.5% were pathological smears. Since this group included a large number of borderline cases, new discrimination limits for clinically relevant pathological findings were set empirically. According to these wider ranges, the fraction of pathological slides amounted to 15.2%. Among these, immature granulocytes, eosinophilia and lymphopenia were the most frequent pathological findings. Microscopic control proved in 57.6% of the total number of smears. This complemental procedure was not found to be time-consuming.