Diagnostic accuracy of a point‐of‐care test using voided urine samples for detection of bacteriuria in dogs with signs of lower urinary tract disease

Abstract

Background: Bacterial urine culture is recommended in dogs suspected of having urinary tract infection (UTI), but there is expense and delay in obtaining such results. Hypothesis/Objective: To determine the diagnostic performance of a rapid immunoassay (RIA) dipstick for detection of bacteriuria using voided urine from dogs with clinical signs of lower UTI. Animals: Twenty-four client-owned dogs. Methods: Voided urine was collected and the RIA performed within 30 minutes. Urine collected by cystocentesis was submitted for aerobic urine culture. McNemar's test and kappa coefficient were calculated to determine agreement between the 2 tests. Results: Nine of 21 dogs (43%) had UTI verified by aerobic urine culture. There was 1 false-negative and no false-positive RIA results. Sensitivity, specificity, positive predictive value, and negative predictive value of the RIA were 89%, 100%, 100%, and 92%, respectively. Conclusions and Clinical Importance: This RIA is promising for correctly identifying whether or not voided urine samples from dogs with lower urinary tract clinical signs have true bacteriuria in a rapid, inexpensive manner. Additional patients should be enrolled in a similar study to determine if diagnostic performance is robust in a large population.

Evaluation of a rapid immunoassay for bacteriuria in dogs

“…The 90.0% sensitivity and 95.2% specificity for the RIA in our study are likely similar to previous publications (97.4% sensitivity and 98.8% specificity) for urine cultures with growth ≥10 3 CFU/mL, and for voided specimens in dogs with LUTS (89% sensitivity and 100% specificity) 6,10 . While confidence intervals in our study were larger than anticipated for evaluation of the sensitivity of this test, they were narrower than those reported by Grant et al 6 No confidence intervals were provided for the other study for comparison 10 . Jacob et al 10 scored and photographed all results and data were interpreted by 1 investigator, our study mimics how the test would be performed in most veterinary practices where the result would be interpreted at the point‐of‐care.…”

“…The prevalence of positive urine cultures in our study (45% ≥ 10 3 CFU/mL) was higher than that reported in studies that either evaluated this RIA or other point‐of‐care assays 6,10,15,16 . This can be attributed to our inclusion criteria, which selected for dogs that were more likely to have bacteriuria.…”

“…The authors of that retrospective study concluded that other variables should be included in future clinical rules to optimize the overall precision for diagnosing UTI 1 . We asked clients to complete a clinical sign survey for their dog at study enrollment that not only included classic LUTS, but also peri‐genital licking as previous studies have indicated these clinical signs are suggestive for UTI in some dogs 5,6 . Because therapeutic outcome was not an aim of this study, we did not determine whether dogs with incontinence improved with antimicrobial therapy.…”

Comparison of a Chromogenic Urine Culture Plate System (UTid+) and Conventional Urine Culture for Canine and Feline Specimens

“…Diagnostic tests may perform differently if limited to a particular population, for example, only those with clinical signs of UTI [ 10 , 11 ]. UTid+, as with all diagnostic tests, should always be interpreted in the context of the clinical patient and should only form part of the clinical decision-making process.…”

“…Sediment analysis, as part of urinalysis, may be used to identify bacteriuria at POC but interpretation likely depends on the skill of the evaluator and has been shown to have low sensitivity [ 9 ]. Other POC tests such as a rapid immunoassay, a urine catalase test, a urine dipstick paddle culture system, and compartmented bacterial culture plates have been evaluated for use in companion animal veterinary medicine and demonstrate variable accuracy [ 10 , 11 , 12 , 13 , 14 ].…”