Relationships among urinary protein‐to‐creatinine ratio, urine specific gravity, and bacteriuria in canine urine samples

Meindl, Alison G.; Lourenço, Bianca N.; Coleman, Amanda E.; Creevy, Kate E.

doi:10.1111/jvim.15377

Cited by 16 publications

(38 citation statements)

References 16 publications

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“…Contrary to the textbook recommendation to avoid the use of urine supernatant for the measurement of USG, 11 which is followed in many clinical studies that use whole urine, 18,25 supernatant is used for the USG measurement and dipstick analysis in other more recent clinical studies. 13,22 Based on our results, either whole urine or supernatant can be used for measuring USG.…”

Section: Discussionmentioning

confidence: 80%

Influence of preanalytic and analytic variables in canine and feline urine specific gravity measurement by refractometer

et al. 2019

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Urine specific gravity (USG), which is usually measured by refractometry, is an important indicator of renal concentrating ability. Few studies have evaluated refractometers with separate scales for canine and feline urine. Variables such as protein content or storage time may influence the USG. We compared the effects of measuring USG with a refractometer with single or separate scales for canine and feline urine, investigated inter- and intra-observer variability, and measured agreement between whole urine and supernatant. We evaluated the correlation between USG and osmolality, the influence of urinary protein on USG and osmolality, and the impact of storage time up to 6 mo. We examined 252 canine and 126 feline samples. Bland–Altman analysis revealed higher USG values of the single-scale refractometer than the dual-scale refractometer, with a mean difference (bias) of < 0.001 for canine and 0.003 for feline specimens. Inter- and intra-observer variability were acceptable. Good agreement was shown between USG of whole urine and supernatant. Correlations between USG and osmolality were excellent (0.98–0.99, p < 0.001). Proteinuria up to 1 g/L had no major impact on USG or osmolality. Storage time had no significant effect on USG. The difference between the refractometers is clinically irrelevant, and the use of a refractometer with separate feline and canine scales is unnecessary. Whole urine and supernatant stored up to 6 mo can both be used for USG measurement. The influence of proteinuria <1 g/L on USG and osmolality is negligible.

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Section: Discussionmentioning

confidence: 80%

Influence of preanalytic and analytic variables in canine and feline urine specific gravity measurement by refractometer

et al. 2019

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“…These findings corroborate those of prior studies that also failed to show correlation between increased UPC and bacteriuria. 5 , 6 …”

Section: Discussionmentioning

confidence: 99%

Prevalence of positive urine culture in the presence of inactive urine sediment in 1049 urine samples from dogs

Strachan

Hales

Fischer

2022

Veterinary Internal Medicne

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Background Urinalysis (UA) is often used to screen for bacterial cystitis, regardless of sediment results, and followed up by quantitative urine culture (UC) for definitive diagnosis. Objectives Determine prevalence of positive UCs in dogs with inactive urine sediments on routine UA. Animals A total of 1049 urine samples with inactive urine sediments and UCs collected from dogs presented to a veterinary specialty hospital between January 2018 and February 2020. Methods Retrospective study of dogs with an inactive urine sediment on routine UA and follow‐up UCs. Signalment, UA findings, proteinuria, and UC results were recorded. Associations among these findings were assessed using multivariate logistic regression carried out using a backward stepwise method. Results Overall prevalence of positive UC was 3.4% (95% confidence interval [CI], 2.4‐4.8). Escherichia coli was the most commonly isolated bacteria. Only naturally voided samples were associated with increased prevalence of positive culture when compared to collection by cystocentesis or a non‐specified method. No statistically significant association with culture positivity was found for urine protein‐to‐creatinine ratio, urine specific gravity, urine pH, breed, age, or sex. Conclusions and Clinical Importance Based on the low prevalence (3.4%) of positive culture in urine samples from dogs with inactive sediment on routine UA and the relatively high cost of UC and sensitivity, cost‐benefit analysis including clinical suspicion of lower urinary tract disease should inform testing decisions, rather than routinely performing cultures on urine samples without active sediments.

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“…There is poor agreement between the presence/absence of bacteriuria and proteinuria and, when comparing dogs with or without clinical signs associated with bacterial growth in urine, there is no significant difference in UPCs. 9 A wide range of UPCs are represented in both categories, likely due to the fact that a large number of diseases, beyond bacterial growth in urine, can contribute to proteinuria.…”

Section: Introductionmentioning

confidence: 99%

Characteristics associated with bacterial growth in urine in 451 proteinuric dogs (2008‐2018)

Grimes

Heseltine

Nabity

et al. 2020

Veterinary Internal Medicne

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Background Urine cultures are frequently recommended to rule out infection as a postrenal cause of proteinuria. Objective Identify characteristics associated with bacterial growth in urine in proteinuric dogs. Animals Four hundred and fifty‐one dogs admitted to a teaching hospital between January 2008 and January 2018 with urine protein‐to‐creatinine ratios (UPCs) >0.5. Methods Retrospective study included dogs with a UPC, urinalysis, and quantitative urine culture (QUC) performed within a 72‐hour period by searching electronic records. Dogs with recent antimicrobial therapy, urine collected by methods other than cystocentesis, or UPC ≤0.5 were excluded. Signalment, comorbidities, serum BUN and creatinine concentrations, urinalysis findings, and QUC results were recorded. The association between these characteristics and presence of bacterial growth in urine was assessed by univariable and multivariable analysis. Results Thirty of four hundred fifty‐one dogs (6.7%) had bacterial growth in urine. Of these, 18 (60.0%) had active urine sediment. Bacterial growth in urine was associated with pyuria (odd ratio [OR] 25.1, 95% confidence interval [CI] 7.9‐79.6, P < .001), bacteriuria (OR 11.1, 95% CI 3.2‐39.1, P < .001), and lower urinary tract disease (OR 6.7, 95% CI 1.9‐23.0; P = .0028). If QUC was prompted based on these criteria, 8/451 (1.8%) of proteinuric dogs would have had undetected bacterial growth. Conclusions and Clinical Importance The proportion of proteinuric dogs with both inactive urine sediment and bacterial growth in urine was low, suggesting that QUC might not be necessary in the evaluation of all proteinuric dogs. An active urine sediment or lower urinary tract disease should prompt QUC for proteinuric dogs.

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Relationships among urinary protein‐to‐creatinine ratio, urine specific gravity, and bacteriuria in canine urine samples

Cited by 16 publications

References 16 publications

Influence of preanalytic and analytic variables in canine and feline urine specific gravity measurement by refractometer

Influence of preanalytic and analytic variables in canine and feline urine specific gravity measurement by refractometer

Prevalence of positive urine culture in the presence of inactive urine sediment in 1049 urine samples from dogs

Characteristics associated with bacterial growth in urine in 451 proteinuric dogs (2008‐2018)

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