We conducted a 10-year retrospective study of all children who had cerebrospinal fluid latex agglutination testing for bacterial antigens performed at 1 tertiary care urban children's hospital. Of the 176 patients with culture-negative meningitis who were pretreated with antibiotics before lumbar puncture, none had a positive latex agglutination study (0 of 176; 95% confidence interval, 0-2%). Latex agglutination studies identified no additional cases of bacterial meningitis beyond those identified by culture in pretreated patients. Clinical decision-making algorithms for the management of pretreated patients at risk for bacterial meningitis should not include latex agglutination testing.