A revalidation and critique of assumptions about urinary sample collection methods, specimen quality and contamination

Abstract

Introduction and hypothesis Midstream urine (MSU) is key in assessing lower urinary tract syndrome (LUTS), but contingent on some assumptions. The aim of this study was to compare the occurrence of contamination and the quality of substrates obtained from four different collections: MSU, catheter specimen urine (CSU), a commercial MSU collecting device (Peezy) and a natural void. Contamination was quantified by differential, uroplakin-positive, urothelial cell counts. Methods This was a single blind, crossover study conducted in two phases. First, we compared the MSU with CSU using urine culture, pyuria counts and differential counting of epithelial cells after immunofluorescence staining for uroplakin III (UP3). Second, we compared the three non-invasive (MSU, Peezy MSU™, natural void) methods using UP3 antibody staining only. Results The natural void was best at collecting bladder urinary sediment, with the majority of epithelial cells present derived from the urinary tract. CSU sampling missed much of the urinary sediment and showed sparse culture results. Finally, the MSU collection methods did not capture much of the bladder sediment. Conclusion We found little evidence for contamination with the four methods. Natural void was the best method for harvesting shed urothelial cells and white blood cells. It provides a richer sample of the inflammatory exudate, including parasitised urothelial cells and the microbial substrate. However, if the midstream sample is believed to be important, the MSU collection device is advantageous.

Urine specimen collection for diagnosing a urinary tract infection-patient experience and preference for urine specimen collection: A Qualitative Study

“…Recent data published as part of this investigation has revealed that this was not the case [14] and that the catheter specimen actually bypassed the cells and sediments that were at the base of the bladder, which were crucial for diagnosing the offending microbes [14]. The ndings from our earlier study also revealed that the spun sediment culture performed on non-invasive samples was the most productive method for identifying bladder pathology and the technique performed with catheter samples had signi cantly more negative results [14].…”

Urine Specimen Collection For Diagnosing a Urinary Tract Infection-Patient Experience and Preference For Urine Specimen Collection: A Qualitative Study

“…Recent data has revealed that this was not the case [14] and that the catheter specimen actually bypassed the cells and sediments that were at the base of the bladder, which were crucial for diagnosing the offending microbes [14].…”

Vaginal or Fecal Contamination Which Contributes to Parasite Existence in Urine Sediment

“…"Because the procedure and steps of urinalysis is easy to conduct, economically affordable, and productive in terms of the result, it is recommended as part of the initial examination of all adult hospitalized patients" [16] and should always be recommended to be reiterated as clinically needed [17]. The rationale and technique of urinalysis are always straightforward [18]. Nevertheless, "various circumstances, whether patient based (excessive exercise.…”