Urine Contamination Prevalence Using a Midstream Collection Device Compared with Clean Voided Collections in Dogs

Collecting clean-caught voided urine samples is minimally invasive, but contamination occurs when urine passes through the nonsterile urethra and external genitalia. Discarding the initial urine stream may reduce these contaminants. This study hypothesized that using a midstream urine collection device would decrease bacterial and cellular contamination as compared with cleanly caught voided urine. This descriptive cross-sectional study collected urine from dogs using standard clean-caught (SCC), midstream collection device (MCD), and cystocentesis (CYS) techniques. Urinalysis and aerobic urine culture characteristics were recorded with each characteristic's prevalence described using percentages and 95% confidence intervals for each mode of collection. Positive urine culture prevalence did not differ between SCC and MCD (adjusted P value = .099); however, CYS had a lower prevalence compared with SCC and MCD (adjusted P values of <.001 [CYS versus SCC] and 0.009 [CYS versus MCD]). For other variables, there was no difference in prevalence when comparing SCC with MCD. There was no identified advantage to collecting urine using an MCD as compared with the SCC technique. Either option is a suitable alternative when CYS is not practical; however, clinicians need to interpret results cautiously because bacterial contamination is more common as compared with CYS.