Urine screen for bacteriuria in symptomatic pediatric outpatients

A retrospective review of 1019 symptomatic pediatric outpatients compared urine dipstick including leukocyte esterase and nitrite to semiquantitative Gram-stained smear of uncentrifuged urine for the identification of specimens that contained greater than or equal to 10(5) organisms/ml as determined by semiquantitative urine cultures. The Gram-stained smear was slightly more sensitive than the dipstick; 97.6% (any microorganisms seen or greater than or equal to 2 organisms/oil immersion field) vs. 90.2% (either leukocyte esterase- or nitrite-positive). The negative predictive value of both screening methods was excellent (99.9 and 99.6%, respectively). The predictive value of a positive screen was low for both methods although the predictive value of a positive screen of the Gram-stained smear did reach 63% when there were greater than or equal to 5 organisms/oil immersion field. Neither method of urine screen should substitute for a urine culture in the symptomatic outpatient. However, the urine dipstick test is a reasonable alternative to a Gram-stained smear for initial patient assessment.