Using a urine dipstick to identify a positive urine culture in young febrile infants is as effective as in older patients

Aim: There is limited evidence about the diagnostic value of urine dipsticks in young febrile infants. The aim of this study was to determine whether urine dipsticks would identify positive urine cultures in febrile infants of less than 90 days of age.

Methods: This study was a subanalysis of a prospective multicentre study developed in 19 Spanish paediatric emergency departments belonging to the Spanish Paediatric Emergency Research Network. It focused on febrile infants of less than 90 days of age admitted between October 2011 and September 2013. A positive urine culture was defined as the growth of ≥ 50,000 cfu/mL of a single pathogen collected by a sterile method.

Results: We included 3401 patients, and 176 (12.8%) female patients and 473 (23.3%) males had a positive urine culture. The leucocyte esterase test showed a mean sensitivity of 82.1% and a mean specificity of 92.4%, with a greater mean negative predictive value for females than males (97.8 versus 94.1%) and a greater mean positive predictive value for males than females (79.4% versus 58%).

Conclusion: The leucocyte esterase test showed the same accuracy in young febrile infants as previously reported findings for older children. It predicted positive urine cultures and also revealed important gender differences.