Urine testing and urinary tract infections in febrile infants seen in office settings: the Pediatric Research in Office Settings' Febrile Infant Study.

OBJECTIVE: To determine the predictors and results of urine testing of young febrile infants seen in office settings.

DESIGN: Prospective cohort study.

SETTING: Offices of 573 pediatric practitioners from 219 practices in the American Academy of Pediatrics Pediatric Research in Office Settings' research network.

SUBJECTS: A total of 3066 infants 3 months or younger with temperatures of 38 degrees C or higher were evaluated and treated according to the judgment of their practitioners.

MAIN OUTCOME MEASURES: Urine testing results, early and late urinary tract infections (UTIs), and UTIs with bacteremia.

RESULTS: Fifty-four percent of the infants initially had urine tested, of whom 10% had a UTI. The height of the fever was associated with urine testing and a UTI among those tested (adjusted odds ratio per degree Celsius, 2.2 for both). Younger age, ill appearance, and lack of a fever source were associated with urine testing but not with a UTI, whereas lack of circumcision (adjusted odds ratio, 11.6), female sex (adjusted odds ratio, 5.4), and longer duration of fever (adjusted odds ratio, 1.8 for fever lasting > or = 24 hours) were not associated with urine testing but were associated with a UTI. Bacteremia accompanied the UTI in 10% of the patients, including 17% of those younger than 1 month. Among 807 infants not initially tested or treated with antibiotics, only 2 had a subsequent documented UTI; both did well.

CONCLUSIONS: Practitioners order urine tests selectively, focusing on younger and more ill-appearing infants and on those without an apparent fever source. Such selective urine testing, with close follow-up, was associated with few late UTIs in this large study. Urine testing should focus particularly on uncircumcised boys, girls, the youngest and sickest infants, and those with persistent fever.