ABSTRACT
OBJECTIVE: Investigators have sought to establish "low-risk" criteria to identify febrile young infants who can be observed safely without antibiotics. Previous studies have used criteria for standard urinalysis to identify suspected urinary tract infection; however, cases of urinary tract infection have been missed. Enhanced urinalysis, using hemocytometer cell count and Gram stain performed on uncentrifuged urine, has been shown to have greater sensitivity and negative predictive value than standard urinalysis. The objective of this study was to evaluate the ability of criteria that incorporate enhanced urinalysis to identify febrile young infants who are at low risk for serious bacterial illness (SBI). METHODS: Institutional guidelines were established in 1999 to evaluate in a retrospective cohort study infants who were /=38.0 degrees C. "Low-risk" criteria included 1) well appearance without focal infection (excluding otitis media); 2) no history of prematurity, illness, or previous antibiotics; 3) peripheral white blood cell count (WBC) between 5 and 15 000/mm(3); 4) absolute band count
