OBJECTIVE: We evaluated the diagnostic utility of the presence and number of cerebrospinal fluid (CSF) bands in distinguishing bacterial from aseptic meningitis among children with CSF pleocytosis. METHODS: We identified retrospectively a cohort of children 29 days to 19 years of age with CSF pleocytosis (> or =10 x 10(6) leukocytes per L) who were treated in the emergency departments of 8 pediatric centers between January 2001 and June 2004 and whose CSF was evaluated for the presence of bands. We performed bivariate and multivariate analyses to determine the ability of CSF bands to distinguish bacterial from aseptic meningitis. RESULTS: Among 1116 children whose CSF was evaluated for the presence of bands, 48 children (4% of study patients) had bacterial meningitis. Bacterial meningitis, compared with aseptic meningitis, was associated with a greater CSF band proportion (0.03 vs 0.01; difference: 0.02; 95% confidence interval: 0.00-0.04) and CSF absolute band count (392 x 10(6) cells per L vs 3 x 10(6) cells per L; difference: 389 x 10(6) cells per L; 95% confidence interval: -77 x 10(6) cells per L to 855 x 10(6) cells per L). In addition, 29% of patients with bacterial meningitis, compared with 18% of patients with aseptic meningitis, had any bands detected in the CSF. After adjustment for other factors associated with bacterial meningitis, however, CSF band presence, CSF absolute band count, and CSF band proportion were not independently associated with bacterial meningitis. CONCLUSION: In this multicenter study, neither the presence nor quantity of CSF bands independently predicted bacterial meningitis among children with CSF pleocytosis.