Suprapubic aspiration bests clean-catch method for urine sampling for UTI in kids below 2
Reliable urine samples are of eminent importance when diagnosing urinary tract infections (UTIs) in children. Noninvasive procedures are convenient but likely to be contaminated.
A recent retrospective study conducted by a group of investigators at the Department of Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark have recently observed that a large number of children will be misdiagnosed if the doctors will rely on clean-catch method (CCU) specimens compared to suprapubic aspiration (SPA).
The study is published in the Journal of Urology.
Anders Breinbjerg and colleagues 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 urinary tract infection who had a clean-catch method and a suprapubic aspiration performed the same day were included. Any growth in suprapubic aspiration was considered significant, whereas for clean-catch method we tested 2 cutoff values of 104 and 105 CFU/ml, along with urinary dipstick results.
The study included a total of 223 children. Using a cutoff of ≥104 CFU/ml, 16.6% of the cohort (37 cases) would be misdiagnosed if relying only on clean-catch method. Using ≥105 CFU/ml, the rate was 24.6% (55 cases). Evaluating leukocyte esterase on urinary dipstick, a large difference between using clean-catch method (sensitivity 94.7%, specificity 14.4%) and suprapubic aspiration (sensitivity 78.9%, specificity 82.2%) became obvious.
As a result, the authors concluded that "a large number of children will be misdiagnosed if relying on clean-catch method specimens compared to suprapubic aspiration. Relying on a negative leukocyte esterase dipstick test to rule out a urinary tract infection is not sufficient in a child with high suspicion of such an infection. Suprapubic aspiration is a safe procedure, and we thus recommend its use to avoid delay of treatment and unnecessary invasive follow up investigations.
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