Low Contamination Rates in Bag Urine Samples Can Be Achieved

Aims: Although international guidelines consider bag urine sample (BUS) as an unreliable way to collect urine in non-cooperative children suspected to have urinary tract infection (UTI), BUS is a commonly used method both in hospital and at home. Contamination of urine samples is believed to be a major problem of this technique. To assess the contamination rate of BUS in our clinical practice we reviewed our microbiological data of the last three years in young children investigated for UTI.
Study Design: Retrospective study.
Place and Duration of Study: Department of Pediatrics, G.B. Morgagni-L. Pierantoni Hospital, Forlì, Italy (2010-2012).
Methodology: Microbiological records of BUS and clean catch urine (CCU), in infants younger than 36 months of age, were retrospectively reviewed. Trained nurses collected BUS according to a standardized procedure. We also reviewed the three-year microbiological records of CCU in children older than 36 months of age. Contamination of a urine sample was defined as the growth of multiple pathogens irrespective to CFU counts.
Results: A total of 583 microbiological records were reviewed, 71% were BUS, 7% and 22% were CCU in children younger and older than 36 months of age respectively. In children younger than 36 months of age, contamination rates were comparable (P=.90) when urine was collected with BUS (16%) or with CCU (14%). In patients older than 36 months of age, contamination rates were significantly reduced (2.4%; P<.001) in CCU compared with both BUS and CCU in younger children.
Conclusion: A good adherence to a standardized nursing procedure for bag urine collection could limit the risk of contamination of urine samples.