Evaluation of the analytical variability of dipstick protein pads in canine urine. (26th March 2018)

• Record Type: Journal Article
• Authors: Giraldi, Marco; Paltrinieri, Saverio; Zatelli, Andrea
• Is Part Of: Veterinary clinical pathology. Volume 47:Number 2(2018)
• Page Start: 246
• Page End: 251
• Publication Date: 2018-03-26
• Subjects: dogs -- proteinuria -- reagent strips -- urinalysis; Veterinary pathology -- Periodicals; 636.089607
• DOI: 10.1111/vcp.12594
• Languages: English
• ISSNs: 0275-6382

Abstract

Abstract : Background: The dipstick is a first‐line and inexpensive test that can exclude the presence of proteinuria in dogs. However, no information is available about the analytical variability of canine urine dipstick analysis. Objectives: The aim of this study was to assess the analytical variability in 2 dipsticks and the inter‐operator variability in dipstick interpretation. Methods: Canine urine supernatants ( n = 174) were analyzed with 2 commercially available dipsticks. Two observers evaluated each result blinded to the other observer and to the results of the other dipstick. Intra‐ and inter‐assay variability was assessed in 5 samples (corresponding to the 5 different semi‐quantitative results) tested 10 consecutive times over 5 consecutive days. The agreement between observers and between dipsticks was evaluated with Cohen's k test. Results: Intra‐assay repeatability was good (≤3/10 errors), whereas inter‐assay variability was higher (from 1/5 to 4/5 discordant results). The concordance between the operators ( k = 0.68 and 0.79 for the 2 dipsticks) and that of the dipsticks ( k = 0.66 and 0.74 for the 2 operators) was good. However, 1 observer and 1 dipstick overestimated the results compared with the second observer or dipstick. In any case, discordant results accounted for a single unit of the semi‐quantitative scale. Conclusions: As for any other method, analytic variability may affect the semi‐quantitation of urinary proteins when using the dipstick method. Subjective interpretation of the pad and, to a lesser extent, intrinsic staining properties of the pads could affect the results. Further studies are warranted to evaluate the effect of this variability on clinical decisions.