Is There a Difference in the Contamination Rates of Urine Samples Obtained by Bladder Catheterization and Clean-Catch Collection in Preschool Children?

Objective: The objective of this study was to compare contamination rates in urine samples obtained by transurethral catheterization and clean-catch methods in preschool children aged 2 to 5 years.

Methods: A retrospective, chart review was performed on patients evaluated in our emergency department over a 6-month period who had a urine culture obtained by either transurethral catheterization or clean-catch methods. The charts were reviewed for urine bacterial colony counts and divided into positive, negative, or contaminated cohorts. Demographic data were collected as well.

Results: Four hundred sixty patients met inclusion for this study. Of these patients, there were 120 samples collected by catheter (26.1%) and 340 samples collected by clean-catch method (73.9%).Female patients comprised 73% of the eligible samples (n = 336), and 27% were male (n = 124). Contamination rates significantly varied by collection method (P < 0.0001), with only 9 contaminated catheter samples (7.5%) and 125 contaminated clean-catch samples (36.76%). Contaminated samples were found in 122 of 336 female urine samples (36.3%), and 12 of 124 male urine samples (9.7%). There were no associations found between contamination rates and age within either sex.

Conclusions: Our study demonstrated a higher urine culture contamination rate in preschool age children in the clean-catch method group compared with the transurethral catheterization group. This finding was particularly strong within the female subset, which could partially be accounted for by the small male sample size.