CYSTOCENTESIS AND URINALYSIS IN ZOOMEDICINE: AN UNDERESTIMATED TOOL FOR LARGE FELID STANDARD HEALTH CHECKS.

Chronic kidney disease (CKD) is a prevalent disease among felids; yet its origin is still poorly understood, and the disease often remains asymptomatic for years, underscoring the need for early diagnosis. This study aimed to investigate the diagnostic value of urinalysis in accurately staging CKD, particularly as routine health checks in large felids often overlook its significance. In this research, ultrasound-guided cystocentesis (UGC) was performed on 50 captive nondomestic felids during routine veterinary health checks under general anesthesia. Urinalysis included microscopic examination of the sediment, measurement of urine specific gravity (USG) and protein to creatinine ratio (UPC). Additional serum kidney markers, such as creatinine and symmetric dimethylarginine, were compared with USG and UPC to assess their diagnostic value as urinary biomarkers. The results demonstrated proteinuria (UPC > 0.4) or borderline proteinuria (UPC 0.2-0.4) in 49% of the animals. Among these cases, 62% were of renal origin, and 38% were postrenal causes. USG was significantly higher in felids with borderline proteinuria compared to those with proteinuria. A moderate, but significant negative correlation between serum parameters and USG was observed, emphasizing the importance of assessing both diagnostic parameters during kidney evaluations. Additionally, felids with CKD have an increased risk of urinary tract infections, necessitating microscopic urinalysis and bacterial culture analysis. Abnormalities, including hematuria, pyuria, crystalluria, and bacteriuria, were found in approximately 38% of cases through microscopical examination of urine. No complications associated with UGC were observed and abnormal findings were detected in 60% of the cases. Based on these results, the authors recommend the inclusion of UGC and urinalysis as standard diagnostic tools in general health checks for nondomestic felids. This approach provides valuable insights into the early detection and staging of CKD, supporting early intervention and supportive medical care to prolong renal health in these animals.

Significance of scattered small echogenic foci floating in urinary bladder as ultrasonography finding in dogs.

BACKGROUND: Despite the prevalence of echogenic foci floating in the urinary bladder seen in ultrasonography in dogs, surprisingly little has been written on its significance, including its potential association with urinalysis. The objective of the study was to determine the diagnostic value of the echogenic foci floating in urinary bladders in dogs. RESULTS: - Cystosonography was performed on 45 dogs. Bladder contents were examined and divided into positive (containing echogenic particles) and negative (absent echogenic particles) groups according to the presence and absence of floating echogenic particles. Five mL of urine was collected via cystocentesis. Urine analysis and culture were done and the relationship between ultrasound evaluation and urinalysis results was investigated. In dogs with bladder echogenic particles in ultrasonography, the prevalence of hematuria, pyuria, bacteriuria, and lipiduria were 88.9%, 92.6%, 29.6%, and 70.3%, respectively. However, in dogs in which echogenic particles were not observed in their bladders, the prevalence of hematuria, pyuria, bacteriuria, and lipiduria was 77%, 50%, 5.5%, and 77%, respectively. There was a significant association between bladder debris and positive urine culture, with an odds ratio of 7.15 (95% confidence interval: 0.81-63.28) compared with matched controls. Furthermore, there was a significant relationship between the presence of floating echogenic particles with pyuria, and urine color ( p ≤ 0.05). CONCLUSION: In conclusion, the present results showed the detection of bladder debris on ultrasound can be a predictor for pyuria and positive urine culture in dogs.

Age-related trends in urine specific gravity in apparently healthy cats.

OBJECTIVES: Urine specific gravity (USG) is the most common method for the estimation of urine concentration in cats. Utilization of USG as a screening tool is easily accessible and is of low cost to the client if strategically utilized in settings of higher diagnostic value. There is currently minimal population information regarding how USG changes across ages in cats. METHODS: Data were collected from electronic pet medical records from more than 1000 hospitals and screened for cats with an apparently healthy clinical status and complete diagnostic information. USG was compared with age in multiple analyses to examine the relationship between the variables. RESULTS: In the absence of other indicators of disease, renal concentrating ability begins to diminish, on average, starting at approximately 9 years of age. By age group, cats aged 11-15 years (1.044, 95% confidence interval [CI] 1.043-1.044) had statistically significantly lower mean USGs compared with cats aged less than 1 year (1.049, 95% CI 1.048-1.051; P <0.001), 1-6 years (1.049, 95% CI 1.049-1.050; P <0.001) or 7-10 years (1.049, 95% CI 1.048-1.049; P <0.001). Cats aged ⩾15 years (1.038, 95% CI 1.036-1.040) had statistically significantly lower mean USGs compared with cats aged less than 1 year (P <0.001), 1-6 years (P <0.001), 7-10 years (P <0.001) or 11-15 years (P <0.001). CONCLUSIONS AND RELEVANCE: Renal concentrating ability begins to diminish, on average, starting at approximately 9 years of age and is progressive as cat age increases. This study provides important and new information to help improve screening practices for disorders of concentrating ability in cats.

Diagnosis of renal lymphoma by Wright-Giemsa-stained cytocentrifuged urine evaluation in a cat.

Lymphoma represents up to 30% of neoplasms diagnosed in cats. Diagnosis of lymphoma in the urinary system by examination of urine sediment has been described in a dog, but apparently not previously in cats. Concurrent samples of serum, EDTA whole blood, and urine were submitted from a 15-year-old spayed female domestic shorthair cat exhibiting weight loss, polyuria, and polydipsia. Hematology and biochemical abnormalities included a mild normocytic, normochromic, non-regenerative anemia; an inflammatory leukogram; and azotemia. Urinalysis evaluation revealed inadequate urine concentration and marked proteinuria. Wet-mount urine sediment examination revealed moderate numbers of leukocytes and erythrocytes. A uniform population of intermediate-to-large lymphocytes was observed on a fresh, Wright-Giemsa-stained preparation from cytocentrifuged urine. The cat was euthanized and necropsy was completed. Bilateral renomegaly was identified and characterized by multifocal, pale-yellow, coalescing, poorly defined, homogenous nodules. Microscopically, these nodules were composed of dense sheets of CD3-positive round cells, consistent with T-cell renal lymphoma. Key clinical message: Lymphoma is a common neoplasm in cats that can affect many organ systems, including the upper urinary tract. This case represents an uncommon method of identifying neoplastic lymphocytes via evaluation of cytocentrifuged urine, and emphasizes the benefits of examining Romanowsky-stained urine sediment in animals.

Diagnostic du lymphome rénal chez un chat par évaluation d'urine cytocentrifugée avec coloration Wright-Giemsa. Le lymphome représente jusqu'à 30 % des néoplasmes diagnostiqués chez le chat. Le diagnostic d'un lymphome du système urinaire par examen des sédiments urinaires a été décrit chez un chien, mais apparemment pas à ce jour chez le chat. Des échantillons simultanés de sérum, de sang total dans un tube avec EDTA et d'urine ont été soumis provenant d'une chatte domestique à poils courts stérilisée de 15 ans présentant une perte de poids, une polyurie et une polydipsie. Les anomalies hématologiques et biochimiques comprenaient une légère anémie normocytaire, normochrome et non régénérative; une formule leucocytaire inflammatoire; et une azotémie. L'analyse d'urine a révélé une concentration urinaire insuffisante et une protéinurie marquée. L'examen microscopique des sédiments urinaires a révélé un nombre modéré de leucocytes et d'érythrocytes. Une population uniforme de lymphocytes de taille intermédiaire à grande a été observée sur une préparation fraîche colorée au Wright-Giemsa à partir d'urine cytocentrifugée. Le chat a été euthanasié et une autopsie a été réalisée. Une rénomégalie bilatérale a été identifiée et caractérisée par des nodules multifocaux, jaune pâle, coalescents, mal définis et homogènes. Au microscope, ces nodules étaient composés de feuilles denses de cellules rondes CD3-positives, compatibles avec un lymphome rénal à cellules T.Message clinique clé :Le lymphome est une tumeur courante chez le chat qui peut affecter de nombreux systèmes organiques, y compris les voies urinaires supérieures. Ce cas représente une méthode rare d'identification des lymphocytes néoplasiques via l'évaluation de l'urine cytocentrifugée et met l'emphase sur les avantages de l'examen des sédiments urinaires avec coloration de Romanowsky chez les animaux.(Traduit par Dr Serge Messier).

Preoperative parameters (signalment, digital radiography, urinalysis, urine microbiological culture) and novel algorithm improve prediction of canine urocystolith composition.

OBJECTIVE: To determine the accuracy of 4 preoperative parameters (signalment, urinalysis, urine microbiological culture, and digital radiography) in predicting urocystolith composition, compare accuracy between evaluators of varying clinical experience and a mobile application, and propose a novel algorithm to improve accuracy. ANIMALS: 175 client-owned dogs with quantitative analyses of urocystoliths between January 1, 2012, and July 31, 2020. METHODS: Prospective experimental study. Canine urocystolith cases were randomly presented to 6 blinded "stone evaluators" (rotating interns, radiologists, internists) in 3 rounds, each separated by 2 weeks: case data alone, case data with a urolith teaching lecture, and case data with a novel algorithm. Case data were also entered into the Minnesota Urolith Center mobile application. Prediction accuracy was determined by comparison to quantitative laboratory stone analysis results. RESULTS: Prediction accuracy of evaluators varied with experience when shown case data alone (accuracy, 57% to 82%) but improved with a teaching lecture (accuracy, 76% to 89%) and further improved with a novel algorithm (accuracy, 93% to 96%). Mixed stone compositions were the most incorrectly predicted type. Mobile application accuracy was 74%. CLINICAL RELEVANCE: Use of the 4 preoperative parameters resulted in variable accuracy of urocystolith composition predictions among evaluators. The proposed novel algorithm improves accuracy for all clinicians, surpassing accuracy of the mobile application, and may help guide patient management.

Urinalysis and culture results of free-catch urine samples in dogs: a randomised controlled trial.

OBJECTIVES: To evaluate the prevalence of bacterial presence in free-catch urine samples preceded by either a standardised prepped ("clean-catch") protocol versus unprepped (non-cleaned) voiding. MATERIALS AND METHODS: The study was a single-centre prospective single-blinded randomised controlled trial. Urine samples were obtained from 100 client-owned dogs presenting for routine evaluation. Dogs were randomly assigned to either the prepped group (preputial or peri-vulvar area cleaned with sterile saline before collection) or the unprepped group (no preliminary cleansing) stratified by sex. Urinalysis and urine culture (blood and MacConkey agar) were performed on all samples. Significant bacterial presence on urine culture was defined as >104 colony forming units (CFU)/mL. RESULTS: There were no statistically significant associations between prepped versus unprepped collection method or sex with a urinalysis positive for bacteriuria. However, on culture, significant bacterial growth was almost five times more likely to be associated with males relative to females (odds ratio 4.59, 95% confidence interval 1.61 to 13.10). The probability of finding a positive culture was not statistically associated with prep method (odds ratio 1.43, 95% confidence interval 0.50 to 4.08). CLINICAL SIGNIFICANCE: For the majority of dogs without clinical signs of urinary tract infection, free-catch urine collection does not result in significant bacteriuria found on analysis or culture. The presence of bacteria found in free-catch samples may be secondary to sample contamination or subclinical bacteriuria. Sample contamination or subclinical bacteriuria may be more prevalent in male dogs.

Evaluation of a urine dipstick protein to urine specific gravity ratio for the detection of proteinuria in dogs and cats.

BACKGROUND: The utility of urine dipsticks for the quantification of proteinuria is limited because of the influence of urine specific gravity (USG). To circumvent the need for urine protein creatinine ratios (UPCR) some have proposed a calculated dipstick urine protein to USG ratio (DUR) for the detection of proteinuria. However, the performance of DUR has not been evaluated in veterinary patients. OBJECTIVES: Evaluate the correlation between DUR and UPCR, while also assessing the effect of urine characteristics on this relationship and evaluating the performance of DUR in detecting proteinuria. ANIMALS: Urine samples from 308 dogs and 70 cats. METHODS: Retrospective cohort study of urinalyses and UPCRs from dogs and cats collected between 2016 and 2021. RESULTS: Both canine and feline urine samples showed a positive moderate correlation between the UPCR and DUR. The correlation was not influenced by the presence of active urine sediment, glucosuria, or urine pH. In detecting canine urine samples with a UPCR >0.5, an optimal DUR of 1.4 had sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 89%, 83%, 96%, and 63%, respectively. In detecting feline urine samples with a UPCR >0.4, an optimal DUR of 2.1 had sensitivity, specificity, PPV, and NPV of 70%, 100%, 100%, and 75%, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Use of the DUR can be a relatively reliable method for identification of proteinuria. However, given its poor NPV, the DUR cannot be recommended for exclusion of proteinuric patients.

Development of a reference interval for urinary ammonia-to-creatinine ratio in feline patients.

BACKGROUND: Disruption of acid-base homeostasis can lead to many clinical problems. Ammonia excretion by the kidneys is critical to maintaining acid-base homeostasis through bicarbonate production. Measurement of ammonia excretion may help determine if the kidneys are properly functioning in maintaining acid-base balance. Reference intervals are essential tools for clinical decision-making but do not currently exist for urinary ammonia-to-creatinine ratio (UACR) in feline patients. OBJECTIVE: This study aimed to generate a reference interval (RI) for UACR in healthy adult cats. METHODS: The study used samples from client-owned adult healthy cats that presented to the University of Florida Primary Care and Dentistry service (n = 92). Physical examination, serum biochemistry, urinalysis, urine ammonia, and creatinine concentrations were measured. Cats were excluded if there were significant abnormalities in their urinalysis or biochemistry panel. The RI for UACR was calculated according to the recommendation of the American Society for Veterinary Clinical Pathology. The UACR was evaluated for correlation with serum bicarbonate, weight, age, and sex. RESULTS: The RI for UACR was 3.4-20.7 with 90% confidence intervals for the lower and upper limits of (3.0-3.7) and (16.0-23.7), respectively. No significant correlation with age, sex, or weight was found. There was no discernable relationship between serum bicarbonate and UACR. CONCLUSIONS: Establishing an RI for UACR in healthy adult cats will allow further studies to determine if changes in UACR are observed during specific disease states.

Point-of-care rapid immunoassay performed on voided urine, refrigerated up to 24 hours, accurately detects bacteriuria.

OBJECTIVE: To collect voided urine from dogs with clinical signs of lower UTI and determine the diagnostic performance of a commercially available rapid immunoassay (RIA) immediately after urine collection and after refrigeration at 4 and 24 hours. ANIMALS: 40 client-owned dogs. METHODS: Aerobic urine culture was performed on urine collected by cystocentesis. Urine samples were collected by voiding, and the RIA performed in triplicate within 30 minutes (time 0) and again in triplicate after 4 and 24 hours of refrigeration. Test precision and agreement between culture results and RIA results at each time point were determined, and factors possibly associated with false results investigated. RESULTS: 14 of 40 dogs (35%) had UTI verified by aerobic urine culture, and all had positive RIA. Three dogs had false positive RIA results. Sensitivity, specificity, positive predictive value, and negative predictive value of the RIA were 100, 88%, 82%, and 100%, respectively, and results were not different after 4 and 24 hours of refrigeration. Precision was excellent. CLINICAL RELEVANCE: This point-of-care RIA, performed on voided urine refrigerated up to 24 hours, rapidly and accurately identifies bacteriuria in dogs with lower urinary tract clinical signs, inexpensively.

Cat Friendly Practice improves feline visits, resulting in increased laboratory testing and increased diagnosis of certain common feline conditions.

OBJECTIVES: Cat Friendly Practices (CFPs) were compared with non-CFP control practices to determine whether CFPs had an increased proportion of clinical visits, number of visits per cat per year and inclusion of diagnostic testing. To measure diagnostic testing behavior, the numbers and types of tests analyzed and clinically relevant findings were compared. METHODS: In a retrospective analysis comparing CFPs and non-CFPs, clinic financial data and associated diagnostic tests from a commercial laboratory for 2018 and 2021 were analyzed. Data were stratified based on visit type and included revenue per visit type, revenue per patient, the number of visits per year and the proportion of visits that included diagnostic testing. Analyses of clinical findings for June 2021 to June 2022 examined clinical findings associated with biochemistry, complete blood count, urinalysis and thyroid testing categories at diagnostic patient visits, the proportion of clinical visits in which each finding was observed, the volume of testing categories as a proportion of clinical visits, and the proportion of diagnostic visits with one, two, three or four testing categories. RESULTS: The average revenue per feline visit and visits that included diagnostic testing were higher at CFPs. There was no difference in the proportion of wellness visits; however, CFPs had higher mean visits per year per patient. CFPs performed diagnostic testing at 12% more clinical visits, and had higher annual revenue per feline patient for all visits and for visits including diagnostic testing. CFPs had higher odds of patients having >1 visit that included bloodwork or urinalysis. They were more likely to include all four testing categories and less likely to include only one category at a diagnostic visit. CFPs identified a higher number of cats with clinical findings. CONCLUSIONS AND RELEVANCE: CFPs exhibited unique diagnostic testing behavior by performing more diagnostic tests more frequently and identifying a higher number of cats with abnormal findings.

[Urinalysis in dogs and cats, part 2: Urine sediment analysis]. / Die Urinuntersuchung bei Hund und Katze, Teil 2: Urinsedimentanalyse.

Examination of the urine sediment is part of a routine urinalysis and is undertaken in order to identify insoluble particles in the urine. This procedure is mainly used in the context of diagnostic evaluation of urinary tract diseases, but may also be useful for the diagnosis of systemic diseases and intoxications. Analysis of fresh urine is recommended as changes in cell morphology, cell lysis and in vitro crystal formation may occur in the course of its storage. Manual urine sediment analysis is still performed in many veterinary practices. Native wet-mount preparations are suitable for the identification and quantification of urine sediment particles. The examination of stained wet-mount preparations or air-dried smears may be necessary to further differentiate cells and to identify bacteria. For several years, automatic urine sediment analyzers have been available in veterinary medicine. These save considerable time and staff resources, however verification of the automatically generated results by an experienced observer remains necessary. Urine sediment particles that are frequently identified and clinically relevant include red blood cells, white blood cells, different types of epithelial cells, crystals, and casts as well as bacteria. Furthermore, parasite eggs, fungal hyphae, lipid droplets, spermatozoa, fibres, hair, mucus, plant parts or environmental contaminations may be found in the urine sediment and result in a complication of the result interpretation.

Biological variation of urinary protein: Creatinine ratio and urine specific gravity in cats.

BACKGROUND: Laboratory results are influenced by presence and severity of disease, as well as preanalytical factors, analytical variation, and biological variation. Biological variation data for urinary protein: creatinine ratio (UPC) and urine specific gravity (USG) in cats are lacking. OBJECTIVES: Determine the biological variation of UPC and USG in cats. ANIMALS: Eighty healthy client-owned cats. METHODS: Prospective study. Urine was collected on days 0, 14, and 56 from all 80 cats to investigate the persistence of borderline or overt proteinuria or suboptimal urine concentration. In 15 of these cats, urine was collected weekly from day 0 to 42 to calculate the index of individuality (II) and reference change value (RCV), and on days 56 and 57 to evaluate day-to-day variability of UPC and USG. RESULTS: Borderline or overt proteinuria (UPC ≥0.2) was present in 18/80 (23%) cats at baseline and persisted on 3 occasions in 2 months in 8/18 (44%) cats. Urine concentration was suboptimal at inclusion (USG <1.035) in 8/80 (10%) cats and at all 3 time points during 2 months in 3/8 (38%) cats. The II of UPC and USG indicated intermediate individuality. The 1-sided RCV was 82% for UPC and 36% for USG. Proteinuria substage was identical on 2 consecutive days in 13/15 (87%) cats, and urine concentrating ability remained the same in all 15 cats. CONCLUSIONS AND CLINICAL IMPORTANCE: A >82% increase in UPC in a healthy cat is not solely attributable to physiological and analytical variation. For USG, a decrease of >36% is considered clinically relevant.

[Urinalysis in dogs and cats, part 1: physical and chemical urinalysis]. / Die Urinuntersuchung bei Hund und Katze, Teil 1: Physikalische und chemische Urinuntersuchung.

The urinalysis of dogs and cats is an important part of the diagnostic evaluation of urinary tract diseases as well as for the identification of systemic diseases. A routine urinalysis consists of a physical and chemical examination of the urine as well as an examination of the urine sediment. Various urine collection methods (free-catch, catheterization, cystocentesis) are available. Each method has multiple advantages and disadvantages. The appropriate method must be chosen individually for each patient depending on the emphasis of the examination. The urine should ideally be examined within 30 minutes of collection as it is prone to change due to time and storage. Physical examination of the urine consists of the determination of urine color, clarity, and specific gravity which provides information regarding the concentration of the urine. The latter is determined by refractometry and needs to be interpreted in the context of the hydration status of the patient. Chemical examination of the urine consists of the determination of the pH value and the presence of blood/hemoglobin/myoglobin, protein, glucose, bilirubin, urobilinogen, nitrite, and ketones. The use of commercially available urine dipsticks is common. These must be stored and used according to the manufacturer's instructions and when interpreting the results, veterinary aspects need to be taken into consideration. The physical and chemical examinations of the urine represent rapid and readily performable methods that provide important information for the diagnosis or the exclusion of numerous diseases.

The relationships between sediment findings and culture results and the presence of proteinuria in canine urine samples.

OBJECTIVES: To assess relationships between urine sediment and microbial culture findings and the presence of proteinuria in canine urine samples, and to assess the change in the percentage of proteinuric samples and urine protein-to-creatinine ratio when urine abnormalities resolve. MATERIALS AND METHODS: Canine urine samples collected via cystocentesis and submitted for culture and contemporaneous urinalysis (including urine protein-to-creatinine ratio) were retrospectively identified. Dogs receiving corticosteroids were excluded. Associations between haematuria (red blood cells>5/high-power field), pyuria (white blood cells>5/high-power field), presence of microorganisms on microscopy, active sediment, and positive culture and proteinuria (urine protein-to-creatinine ratio>0.5) were investigated. Patient characteristics were considered possible confounders. In dogs with repeat urinalysis, the associations between active sediment and positive culture resolution on proteinuria and urine protein-to-creatinine ratio were assessed. RESULTS: One hundred and ninety-two of 491 samples were proteinuric (39.1%). Age was positively associated with proteinuria. In the multivariable analysis corrected for age, active sediment was the only variable significantly associated with proteinuria (adjusted odds ratio: 2.12; 95% confidence interval: 1.44 to 3.11); however, only 49.8% of samples with active sediment were proteinuric. Neither resolution of active sediment nor positive culture were associated with reduced proportions of proteinuric samples (from 57.9% to 42.1% and from 40.0% to 25.0%, respectively) or significant reductions in urine protein-to-creatinine ratio (median change: -0.16 and -0.14, respectively). CLINICAL SIGNIFICANCE: Attributing proteinuria to urinalysis abnormalities or a positive urine culture in canine cystocentesis samples is not supported by our findings, and could result in alternative causes of proteinuria (e.g. renal proteinuria) being overlooked.

Comparison of cystocentesis versus home sampling to determine urinary protein: Creatinine ratio and urine specific gravity in cats.

BACKGROUND: Urinalysis is necessary for the diagnostic evaluation of chronic kidney disease in cats. Performing cystocentesis is not always feasible, but data comparing urine obtained by cystocentesis in the clinic with voided samples collected at home are lacking in cats. OBJECTIVES: To compare urinary protein:creatinine ratio (UPC) and urine specific gravity (USG) and to detect clinically relevant changes in proteinuria substage or urine concentration between urine collected at home and in-clinic by cystocentesis in cats. ANIMALS: Ninety-two healthy and diseased client-owned cats. METHODS: Prospective study. Owners collected voided urine at home and within 1 to 15 hours, cystocentesis was performed in the clinic. RESULTS: In a subset of motivated owners, 55% succeeded in collecting urine at home. Overall, UPC was higher (mean ±SD difference = 0.09 ±0.22; P < .001) and USG was lower (mean ±SD difference = -0.006 ±0.009; P < .001) in cystocentesis samples than in voided urine. Substantial agreement existed between sampling methods for UPC (weighted к = 0.68) and USG (к = 0.64) categories. A different proteinuria substage (UPC < 0.2, 0.2-0.4, >0.4) was present in paired urine samples from 28% of cats. In 18% of cats, urine concentrating ability (USG < or ≥1.035) differed between both samples. CONCLUSIONS AND CLINICAL IMPORTANCE: Home sampling of urine is a valid alternative to cystocentesis in cats. However, because clinically relevant differences in UPC and USG were present in 28% and 18% of cats, respectively, by the same collection method for monitoring each cat is advised.

Assessment of inter-observer agreement among experienced and inexperienced observers and an automated device for dipstick urinalysis in dogs and cats.

Standard visual urine dipstick analysis (UDA) is performed routinely in veterinary medicine; results can be influenced by both the operator and the method. We evaluated the agreement of results for canine and feline urine samples analyzed using a 10-patch dipstick (Multistix10SG; Siemens), both visually under double-anonymized conditions by students and a laboratory technician, and with an automated device (AD; Clinitek Status, Siemens). The mean concordance for semiquantitative urinalysis results between students and the technician and between students and the AD was fair (κ0.21-0.40) in dogs and cats; concordance was moderate between the technician and the AD (κ0.41-0.60) in dogs and good (κ0.61-0.80) in cats. For pH, the mean concordance between students and the technician and between the technician and the AD was good (ρ0.80-0.92) in dogs and cats; concordance was good between students and the AD (ρ0.80-0.92) in dogs and moderate (ρ0.59-0.79) in cats. Repeatability was higher (p < 0.001) for the technician and the AD than for a student. We found good agreement between UDA performed by an experienced operator and an AD in dogs and cats but found low reproducibility and low repeatability for urinalysis performed by an inexperienced operator.

Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment.

OBJECTIVES: Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment. MATERIALS AND METHODS: Cats and dogs with contemporaneous urine dipstick, microscopic sediment analysis and microbiological culture and sensitivity results over a four-year period (2016 to 2020) were retrospectively identified. Dogs and cats with active urine sediments (at least five erythrocytes and/or five leukocytes per high-power field) and/or spermaturia were excluded. Association between urine pH, haem dipstick result, protein dipstick result and urine protein:creatinine ratio with bacteriuria were evaluated using binary logistic regression analysis. Likelihood ratios for bacteriuria were calculated at different diagnostic thresholds. RESULTS: A total of 668 and 169 dog and cat urine samples were included. Of these, 166 dogs (25%) had a positive urine culture, whilst only 29 cats (17%) had a positive urine culture. In dogs and cats, any positive haem dipstick result was significantly associated with bacteriuria, although only a ≥4+ haem positive result in dogs was associated with a small increase in the likelihood of a positive urine culture, and positive likelihood ratios did not support the use of haem dipstick results as a screening test for bacteriuria in cats. pH, urine protein:creatinine ratio and protein dipstick results were not associated with bacteriuria. CLINICAL SIGNIFICANCE: Our findings provide proof of concept that haem dipstick pad results in dogs with inactive sediment and without spermaturia might be useful as a screening test for bacteriuria, although further studies are required to confirm these findings.

Analytical performance evaluation of two automated urine chemistry analysers using two levels of commercially available quality control material.

OBJECTIVE: Evaluate two point-of-care urine chemistry analysers, VetScan SA and VetLab UA using assayed, bilevel (two concentrations) urine quality control material to determine if performance is acceptable for semiquantitative clinical urine chemistry analysis. MATERIALS AND METHODS: Normal and abnormal urine quality control material sent to 23 veterinary practices was evaluated three times by each clinic on in-clinic automated urinalysis instruments. Accuracy, precision and clinical utility were evaluated. RESULTS: Normal urine quality control material: Results for blood, glucose, ketones and bilirubin were 100% accurate and precise for both analysers, and pH values were accurately acidic to neutral. However, pH from VetScan SA had clinically significant negative bias. Abnormal urine quality control material: VetScan SA: blood, microalbumin and bilirubin were 100% accurate; glucose, ketones, and protein demonstrated ≤10% inaccuracy; pH demonstrated 34% inaccuracy. VetLab UA: blood, ketones and bilirubin were 100% accurate; glucose and protein demonstrated ≤10% inaccuracy; pH was 100% accurately neutral to alkaline. CLINICAL SIGNIFICANCE: VetScan SA had marked negative pH bias versus VetLab UA resulting in clinically significant, overly acidic results. Specific gravity, nitrite, and leukocyte test pads should not be used. Both instruments had excellent performance in normal quality control material. While blood, glucose, protein and bilirubin are correctly identified as present in abnormal quality control material, exact concentrations cannot be interpreted due to imprecision. Only semiquantitative results, not numerical values implying quantification, should be reported from urine test strips.

Iodinated non-ionic contrast medium does not inhibit Escherichia coli growth in ex vivo inoculated canine urine.

OBJECTIVE: To investigate the effect of iohexol on standardized quantitative urine culture results in dogs. The authors hypothesized that the presence of iohexol in inoculated urine samples would result in lower bacterial concentrations (CFU/mL) and, therefore, decrease culture sensitivity. SAMPLE: Urine samples were aseptically collected during cystoscopy from a single client-owned dog untreated with antimicrobials. PROCEDURES: An experimental controlled study. The urine sample was divided into 38 aliquots (0.5 mL each) that were used as negative controls or inoculated with an equal amount of Escherichia coli (105 CFU/mL). Different volumes (0.1 and 0.5 mL) of contrast or saline were added to the aliquots and quantitative culture results were compared. Two different incubation times between the preparation of aliquots and culture were evaluated (15 minutes and 24 hours). RESULTS: All aliquots from samples inoculated with E. coli (positive controls and iohexol-group) had the same reported quantitative result (104 CFU/mL). No growth was reported for the negative controls. Iohexol did not show any anti-E. coli properties in canine urine cultures for dilutions up to 1:2 contrast:urine and concentrations up to 120 mgI/mL. No difference was reported when iohexol was incubated with inoculated urine for 15 minutes or 24 hours. CLINICAL RELEVANCE: Based on the experimental in vitro conditions described, administration of iohexol before the collection of urine during urologic procedures does not negatively impact the isolation and growth of E. coli.

Evaluation of a smartphone-based colorimetric method for urinalysis dipstick readings in cats.

OBJECTIVES: The aim of the study was to compare the diagnostic performances of a smartphone-based colorimetric method (SBCM) for urinalysis with a semi-automated point-of-care (POC) analyser using standardised solutions and cat urine. METHODS: Artificial solutions (negative and positive quality controls, and purposely designed artificial urine) and natural urine from 216 cats were used. Two urine reagent strips were simultaneously dipped in each sample. One dipstick was read by the SBCM and the other by the POC analyser at the same time. Results for pH, proteins, bilirubin, 'blood', glucose and ketones were considered. Overall agreement and sensitivity, specificity and accuracy of the SBCM were determined based on selected cut-offs. RESULTS: For the artificial solutions, 80 comparisons were obtained for each analyte and each expected concentration. The overall agreement (exactly the same result) between the two methods was 78.4%. SBCM sensitivity, specificity and accuracy were 99.0%, 100% and 99.3%, respectively. The correlation between the two methods was almost perfect (Cohen's kappa coefficient = 0.9851). For natural urine samples, the overall agreement (including pH) was 68.6%. Using optimal cut-offs for the SBCM determined from the results of analysis of artificial solutions, the sensitivity, specificity and accuracy of the SBCM were 100%, 76.02% and 80.5%, respectively. In this situation, the correlation between the two methods was moderate (Cohen's kappa coefficient = 0.5401). This was mostly due to a high rate of false-positive results for bilirubin (61.1%). CONCLUSIONS AND RELEVANCE: With proper cut-off use (ie, considering positive or negative results) the SBCM evaluated here has a perfect sensitivity and appropriate diagnostic performances for proteins, 'blood', glucose and ketones. Based on these experimental data, this method appears suitable for dipstick urinalysis but positive results for bilirubin and proteins have to be confirmed.