Bacteremia in private pediatric practice.

The capillary white blood cell count and differential, a test easily done in office practice, was used in unexplained febrile illness of infants and toddlers to help distinguish those babies most likely to have bacteremia who would benefit from blood culture and early bacteriologic diagnosis. Four criteria were used as indicators suggestive of bacterial infection: white blood cell count greater than or equal to 15,000/cu mm, total segmented neutrophils greater than or equal to 10,000/cu mm, total band cells greater than or equal to 500/cu mm, and total polymorphonuclear leukocytes (segmented neutrophils plus band cells) greater than or equal to 10,500/cu mm. These measurements were found helpful in separating a small group of bacteremic babies at high risk of complications from a large group of babies who recovered without antibiotic treatment and without complications. There were 146 febrile illnesses recorded in babies 3 to 24 months of age; bacteremia was proven in eight of these. Three or four blood cell count criteria were fulfilled in seven of the eight bacteremic babies and in only ten (7.2%) of the remaining 138 febrile illnesses (P < .001 by chi 2 test).