Contamination in Urine Samples Collected Using Bladder Stimulation and Clean Catch Versus Urinary Catheterization in Infants Younger Than 90 Days

Objectives The objective of this study was to compare the risk of contamination for urine samples collected from patients younger than 90 days using 2 different techniques: bladder stimulation and "clean catch" (CC) and urinary catheterization (CATH). Methods A case-control study was carried out in the pediatric emergency room of a tertiary hospital between January 2016 and September 2017. All urine samples collected from patients younger than 90 days by CC or CATH were included. The incidence of contaminated urine samples was compared for both methods, and the risk of contamination was estimated using univariate and multivariate analyses. Results A total of 473 urine samples were collected, 310 via CATH (65.5%) and 163 via CC (34.5%). The median age was 1.4 months (interquartile range, 0.8-2.1 months), and 54.1% were males. Seventeen patients had a history of urinary tract infection (3.6%), and 16 were diagnosed with a congenital urorenal anomaly (3.4%). Sixteen urine samples were found to be contaminated (3.4%): 5 collected via CATH (1.6%) and 11 via CC (6.8%). The univariate analysis revealed a greater risk of contamination in specimens obtained using CC versus CATH (odds ratio, 4.41; 95% confidence interval, 1.51-12.93), and the multivariate analysis confirmed CC collection as an independent risk factor for contamination (odds ratio, 5.61; 95% confidence interval, 1.83-17.19). Conclusions The number of contaminated urine samples in infants younger than 90 days in our pediatric emergency department is low. However, using the CC urine collection technique seems to be an independent risk factor for sample contamination.