Pitfalls in Diagnosing Urinary Tract Infection in Children below the Age of 2: Suprapubic Aspiration vs Clean-Catch Urine Sampling.

Abstract

Reliable urine samples are of eminent importance when diagnosing urinary tract infections (UTIs) in children. Noninvasive procedures are convenient but likely to be contaminated. This study aimed to compare the diagnostic accuracy of urine samples obtained by the midstream clean-catch method (CCU) to urine obtained by suprapubic aspiration (SPA) and to evaluate the ability of urinary dipstick to predict true infection. Retrospectively, data on children <2 years of age seen at our center for suspicion of UTI who had a CCU and a SPA performed the same day were included. Any growth in SPA was considered significant, whereas for CCU we tested 2 cutoff values of 10⁴ and 10⁵ CFU/ml, along with urinary dipstick results. A total of 223 children were included. Using a cutoff of ≥10⁴ CFU/ml, 16.6% of the cohort (37 cases) would be misdiagnosed if relying only on CCU. Using ≥10⁵ CFU/ml, the rate was 24.6% (55 cases). Evaluating leukocyte esterase on urinary dipstick, a large difference between using CCU (sensitivity 94.7%, specificity 14.4%) and SPA (sensitivity 78.9%, specificity 82.2%) became obvious. A large number of children will be misdiagnosed if relying on CCU specimens compared to SPA. Relying on a negative leukocyte esterase dipstick test to rule out a UTI is not sufficient in a child with high suspicion of such an infection. SPA is a safe procedure, and we thus recommend its use to avoid delay of treatment and unnecessary invasive followup investigations.