Automated differential white blood cell counts in the young pediatric population

The significance of the white blood cell differential in young children is not well defined. The relationship of the new automated flow cytometric techniques to the manual differential, moreover, has not been established for this age group. We compared automated white counts with manual differential white counts performed on peripheral blood collected from children younger than 3 years. We compared these results with those obtained on adults. The automated neutrophil and lymphocyte counts showed poorer correlations (r=0.86 and 0.90, respectively) with manual counts compared with the adult results (r = 0.94 and 0.96). Correlations for eosinophils, monocytes, and basophils also were lower. When flagged and nonflagged samples were analyzed separately, correlations of nonflagged differentials with manual counts were better but remained lower than correlations for adults. Seventy-one percent of the specimens 'flagged' abnormalities that required microscopic evaluation, compared with 33% in the adult hospital population.