Urinalysis effective to exclude UTI in febrile infants younger than 60 days

Reference

Tzimenatos L, Mahajan P, Dayan PS, et al, for the Pediatric Emergency Care Applied Research Network (PECARN). Accuracy of the urinalysis for urinary tract infections in febrile infants 60 days and younger. Pediatrics 2018;141(2):e20173068.

Synopsis

The authors enrolled a convenience sample (ie, not every patient) of 4147 febrile infants presenting to 1 of 26 emergency departments in the United States who were younger than 60 days and who had blood and urine cultures as well as a urinalysis on urine obtained via catherization or suprapubic aspiration. A positive urinalysis result was considered to be any leukocyte esterase (even trace), nitrites, or pyuria (> 5 white blood cells per high-power field). The prevalence of UTI (at least 50,000 colony-forming units/mL) was 7%, and only 9.3% of these children had bacteremia. The sensitivity of a positive urinalysis was 94% (95% CI 91% - 97%) and 100% (87% - 100%) in infants with bacteremia. The specificity was similarly high: 91% (90% - 91%). These statistics translate to a positive predictive value of 43% (39% - 47%) and a negative predictive value of 100% (99% - 100%). Using a lower cutoff for UTI of at least 10,000 colony-forming units/mL, the sensitivity dropped to 87% (83% - 90%) but the specificity remained the same (91%). These latter results are similar to those from another study of older children (Am J Emerg Med 2009;27(8):930-932).