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.

[Urinalysis in dogs and cats, part 1: physical and chemical urinalysis]

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.

Cystatin C and Iris: Advances in the Evaluation of Kidney Function in Critically Ill Dog

Critically ill hospitalized dogs are subject to certain complications, being acute kidney injury (AKI) a common one. Early diagnosis is crucial, and Cystatin C (CysC) is a reliable and early biomarker. The International Society of Renal Interest (IRIS) states that AKI severity can be assessed by mild changes in creatinine serum levels or reduction of urine output that cannot be considered biomarkers of renal injury but failure or insufficiency. Twenty-eight dogs admitted to the Intensive Care Unit under risk factors for the development of AKI were evaluated. Blood samples were collected for determination of sCr and CysC at admission and after 24, 48, and 72 h. Urine output was measured by daily monitoring, measured by collection in a closed system. The results showed the incidence of AKI was 67.9% based on the IRIS criteria and 78.6% based on cystatin C in critically ill patients' dogs. The measurement of serum cystatin C immediately on admission to the ICU was superior in the early identification of patients with AKI when compared to the IRIS classification and serum creatinine in critically ill dogs.

Effect of domperidone (leisguard®) on antibody titers, inflammatory markers and creatinine in dogs with leishmaniosis and chronic kidney disease

Background

Immunotherapeutic drugs, such as domperidone, have been shown to be promising treatments against canine leishmaniosis (CanL), but limited data are available. The aim of this pilot study (therapeutic, prospective and non-controlled) was to evaluate the effect of domperidone on serum antibody titers of Leishmania infantum, globulins, gamma globulins, acute-phase proteins (e.g. C-reactive protein [CRP]), big endothelin-1 (big ET-1), serum creatinine (SC) and proteinuria in dogs with leishmaniosis affected by chronic kidney disease (CKD).

Methods

Dogs were recruited if “exposed” to or “infected” with L. infantum and affected by CKD (IRIS stage 1 [proteinuric] or IRIS stage 2–3a [SC < 3.5 mg/dl; proteinuric or non-proteinuric]). After inclusion, an oral suspension of domperidone was administered, and the dogs were followed up for 180 days, with checks at 30, 60, 90 and 180 days after initial treatment.

Results

Of the 14 recruited dogs, nine showed a statistically significant reduction in SC (χ² = 9.1, df = 3, P = 0.028), but not in the urine protein/creatinine ratio (χ² = 6.43, df = 3, P = 0.092). All dogs showed a significant reduction in antibody titers for L. infantum (χ² = 9.56, df = 2, P = 0.008), globulins (χ² = 11.08, df = 3, P = 0.011) and gamma globulins (χ² = 12.38, df = 3, P = 0.006) during the study period. There was also a statistically significant reduction in CRP (χ² = 16.7, df = 3, P = 0.001), but not in big ET-1 (χ² = 2.04, df = 3, P = 0.563).

Conclusions

This study provides preliminary results on the ability of domperidone to improve SC and reduce anti-L. infantum antibody titers, globulins, gamma globulins and CRP in dogs with leishmaniosis and CKD.

Graphical abstract

Clinical and Histopathological Features of Renal Maldevelopment in Boxer Dogs: A Retrospective Case Series (1999-2018)

Simple Summary

This study describes clinical findings in Boxer dogs with renal maldevelopment and proposes a possible mode of inheritance. Medical records of 9 female Boxer dogs, older than 5 months and with a clinical diagnosis of proteinuric chronic kidney disease prior to one year of age, showed the presence of polyuria and polydipsia, decreased appetite, weight loss, lethargy and weakness in all affected dogs. Common laboratory findings were proteinuria and diluted urine, non-regenerative anemia, azotemia, hyperphosphatemia, hypoalbuminemia and hypercholesterolemia. Histopathology of the kidneys identified the presence of immature glomeruli in all dogs. In 7 out of 9 related dogs, the pedigree analysis showed that a simple autosomal recessive trait may be a possible mode of inheritance. Renal glomerular immaturity should be suspected in Boxer dogs with a history of polyuria, polydipsia, decreased appetite, weight loss, lethargy, weakness and proteinuria. A prompt diagnosis of renal maldevelopment, potentially hereditary, may help to evaluate if relatives of the affected dogs might be at risk, thus assisting clinicians in reaching an early diagnosis. A routine clinical renal screening evaluation in this breed, especially when this disease is suspected, should be strongly recommended.

Abstract

Renal maldevelopment (RM) has been proposed to replace the old and sometimes misused term “renal dysplasia” in dogs. Although renal dysplasia has been described in Boxers, hereditary transmission has only been hypothesized. This study reports clinical and renal histological findings in Boxer dogs with RM, proposing a possible mode of inheritance. Medical records of 9 female Boxer dogs, older than 5 months and with a clinical diagnosis of chronic kidney disease prior to one year of age, were retrospectively reviewed. Polyuria and polydipsia (PU/PD), decreased appetite, weight loss, lethargy and weakness were described in all affected dogs. Common laboratory findings were proteinuria, diluted urine, non-regenerative anemia, azotemia, hyperphosphatemia, hypoalbuminemia and hypercholesterolemia. Histopathology of the kidneys revealed the presence of immature glomeruli in all dogs, which is consistent with RM. In 7 related dogs, the pedigree analysis showed that a simple autosomal recessive trait may be a possible mode of inheritance. Renal maldevelopment should be suspected in young Boxer dogs with a history of PU/PD, decreased appetite, weight loss, lethargy, weakness and proteinuria. Due to its possible inheritance, an early diagnosis of RM may allow clinicians to promptly identify other potentially affected dogs among the relatives of the diagnosed case.

Urine creatinine concentration and urine protein-to-creatinine ratios in healthy nonracing Greyhounds

BACKGROUND

Serum creatinine concentrations are higher in Greyhounds when compared with nonsighthound breeds. Greyhounds might also have higher urine creatinine concentrations compared with other breeds, which could affect urine protein-to-creatinine ratio (UPC) references.

OBJECTIVES

We aimed to determine the UPC reference intervals (RIs) in healthy nonracing Greyhounds and compare this with UPC values in a group of healthy nonsighthounds and with the current International Renal Interest Society (IRIS) guidelines.

METHODS

The study used an observational cross-sectional design, involving clinically healthy, nonracing Greyhounds (n = 98) and nonsighthound dogs of similar weight, age, and sex (n = 24). Packed cell volumes, total solids, urine protein concentrations, serum and urine creatinine concentrations, urine specific gravity (USG) measurements, and UPCs were determined. Linear regression was used to compare urine creatinine and urine protein concentrations, relative to the USG measurements, between Greyhound and nonsighthound groups. Greyhound UPC RIs were determined using nonparametric methods and compared with UPC values in nonsighthounds and current IRIS guidelines.

RESULTS

Mean urine creatinine concentrations, adjusted for USGs, were approximately 22% higher in Greyhounds compared with nonsighthounds (P = .002). Mean urine protein concentration (P = .46) and UPC (P = .1) were not significantly different between Greyhounds and nonsighthounds. The upper limit of the Greyhound UPC RI was 0.20 or 0.42, depending on whether strict or moderate exclusion criteria were applied, respectively.

CONCLUSIONS

Greyhounds have higher urine creatinine concentrations than nonsighthounds. Although the suggested RI for UPCs in Greyhounds is slightly lower than the cut-offs recommended in generic canine IRIS guidelines, this difference is not likely to be clinically significant.

Urinary calcium assessment and its relation with age, sex and Encephalitozoon cuniculi serological status in otherwise healthy pet rabbits

BACKGROUND

Urinary calcium excretion by rabbits is set proportionately higher than that of other species, giving the rabbit urine its characteristic cloudy appearance. During pregnancy, lactation and growth, or when metabolic disorders interfere in the renal excretion of calcium, it is reported that less calcium is excreted and the urine appears clear. The quantification of the calcium concentration in the urine of rabbits may be of importance in the management of diseases that affect calcium metabolism, especially in kidney disease; however, reference intervals for urinary calcium concentration (UC) are unreported in pet rabbits.

METHODS

Prospective data from 63 healthy pet rabbits were evaluated. An inhouse modified Arsenazo III technique, without acidifying the urine, was used to determine the reference intervals for UC and UC:creatinine ratio. Urinary protein:creatinine ratio, UC, UC:creatinine ratio, urinary gamma-glutamyl transferase concentration (UG), UG:creatinine ratio, phosphorus, plasma total calcium, plasma creatinine, urea and ionised calcium were assessed according to age, sex, neutered status, urine collection method and Encephalitozoon cuniculi IgG status in healthy rabbits.

RESULTS

The reference intervals for UC and UC:creatinine ratio were 4.2-31.1 mg/dl (1.03-7.78 mmol/l) and less than 0.3, respectively. The results showed that none of these variables was influenced by the parameters evaluated, except for the phosphorus value, which was higher in pet rabbits aged up to 3 years compared with those over 3 years, suggesting that published reference values for plasma phosphorus in rabbits should be adjusted according to age.

CONCLUSION

The modified Arsenazo III technique described in the present work and the established reference values for UC and UCC in pet rabbits could be useful in the management of kidney disease in rabbits. The results showed that E cuniculi IgG seropositivity has no influence on the variables of renal interest in otherwise healthy rabbits.

Prevalence of Proteinuria in Owned Dogs from Italy: A Multicentric Study

Even though proteinuria is related to different causes, when it is persistent and associated with inactive urinary sediment, it is primarily due to kidney disease. Early detection of proteinuria allows us to identify several pathological conditions. The aim of the study was screening a canine population not known as being proteinuric, by the urinary dipstick. The study was carried out in seven Italian veterinary clinics during a period of six weeks. Dogs were enrolled with no restriction of sex or age. Females in estrus, dogs with signs of genitourinary diseases, or those previously diagnosed with proteinuric nephropathy were excluded. Dogs were considered “nonproteinuric” (NP) in case of negative dipstick test or “suspected proteinuric” (SP), if positive at the dipstick. When possible, proteinuria was confirmed by UPC ratio. A total of 1156 dogs were evaluated: 414 were from northern Italy and 742 from southern Italy. Based on dipstick test, 655 (56.6%) dogs were NP, while 501 (43.3%) were SP. Among the NP dogs 225 out of 414 (54.3%) were in northern Italy and 430 of 742 (57.9%) in southern Italy. One hundred eighty-nine of 414 (45.7%) SP dogs were identified in northern Italy and 312 of 742 (42.1%) in southern Italy. No statistical difference was found between the North and the South of Italy. UPC was available in 412 out of 501 SP samples: proteinuria was confirmed in 263 (63.86%) samples. Results from our study showed a high percentage of suspected proteinuric dogs, apparently not affected by renal diseases, together with the absence of statistically significant differences based on geographical area.

Urinalysis and Urinary GGT-to-Urinary Creatinine Ratio in Dogs with Acute Pancreatitis

In acute pancreatitis (AP), kidney injury (KI) can occur. Urinalysis and some urinary biomarkers have been proposed as prognostic tools in human AP. The aim of the study was to evaluate urinalysis and urinary GGT-to-urinary creatinine (uGGT/uCr) in canine AP and their association with possible outcomes. AP diagnosis was based on clinical and laboratory parameters, abnormal SNAP^® cPL™ test and compatible imaging. Urinary KI (uKI) was defined if dogs had urinary casts and/or proteinuria. Dogs (n = 70) were divided in survivors and non-survivors according to the 15-day outcome. Data were analyzed using statistical software. Seventy dogs were retrospectively included, of which 24 dogs (34%) died. uKI was detected in 36 dogs (37%) which was associated with mortality (p = 0.01, Odds ratio (OR) 3.9, 95% CI 1.3–11.56). Non-survivors showed higher dipstick bilirubin levels than survivors (p = 0.0022). By excluding active sediments, urine protein-to-creatinine ratio (UPC) ≥2 was associated with mortality (p = 0.001, OR 47.5, 95% CI 4–571.9). The uGGT/uCr was available in 40 dogs, although no association of this factor with any outcome was found. The UPC ≥2 can be a negative prognostic factor in canine AP and further studies on uGGT/uCr are warranted.

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

Background

Proteinuria is a marker of chronic kidney disease in dogs and a risk factor for increased morbidity and death. Predictive models using the results of readily available screening tests could foster early recognition.

Objective

To determine whether urine specific gravity (USG) and semiquantitative category of dipstick protein can be used to predict urinary protein‐to‐creatinine ratio (UP : C) and to examine the effect of urine culture results on UP : C in dogs.

Animals

Three hundred ninety‐four dogs (482 visits) presented to a university Community Practice Clinic or Veterinary Teaching Hospital between January 2011 and November 2015.

Methods

Retrospective study. Medical records were searched to identify dogs for which urinalysis, UP : C measurement, and urine culture testing were performed during a single hospital visit. Urine specific gravity, UP : C, dipstick protein concentration, and findings of urine sediment analysis and urine culture were recorded. Regression or Spearman correlation analysis was used to test for relationships between UP : C and USG within dipstick categories and between UP : C and bacterial colony‐forming units per milliliter, respectively. Cohen's kappa test was used to evaluate agreement between urine culture and UP : C testing.

Results

There were significant (P < .05) weak negative correlations (R² range, 0.14‐0.37) between UP : C and USG for all nonnegative urine protein dipstick categories. The presence of a positive urine culture did not agree with the presence of abnormal UP : C (κ = −0.06).

Conclusions and Clinical Importance

Within dipstick protein categories, UP : C cannot be accurately predicted from USG. Repeating UP : C measurement after resolution of urinary tract infection is advisable.

Effect of common storage temperatures and container types on urine protein : creatinine ratios in urine samples of proteinuric dogs

Background

Preanalytic protein adsorption to polymer and glass container surfaces may decrease urine protein concentration measurements and urine protein: creatinine ratios (UPC).

Hypothesis/Objectives

Urine stored in PC or glass containers will have lower UPC than urine stored in HP containers. The specific objective was to determine whether clinically relevant differences in UPC would be detected after storage in glass, PC, or HP containers using common storage times and temperatures.

Animals

Twelve client‐owned dogs with proteinuria.

Methods

Prospective, nonmasked study, divided into 2 phases. The first phase was a pilot study involving multiple (n = 5) measurements at each storage condition using 24‐hours urine samples from 2 dogs with persistent renal proteinuria of different magnitude. The second phase used urine samples from 10 dogs with proteinuria of variable magnitude. Sample aliquots were stored in HP, PC, and glass containers at 24°C for 4 hours, 4°C for 12 hours, and −20°C for 72 hours. The UPC of each was measured after storage and compared with baseline.

Results

Statistically significant but clinically irrelevant differences were found in phase 1. In phase 2, storage conditions did not affect urinary protein or creatinine concentrations or UPC.

Conclusions and Clinical Importance

Collection and storage of canine urine samples in clean HP, PC, or glass containers at 24°C for 4 hours, 4°C for 12 hours, or −20°C for 72 hours is unlikely to result in clinically relevant decreases in measured UPC values.

Proteinuria in Apparently Healthy Elderly Dogs: Persistency and Comparison Between Free Catch and Cystocentesis Urine

BACKGROUND

Up to 25% of elderly humans have proteinuria, often associated with underlying lesions. Data concerning the presence of proteinuria in elderly dogs is scarce.

OBJECTIVES

To describe the presence and persistence of proteinuria and to compare urinary protein : creatinine ratio (UPC) between free catch and cystocentesis urine samples in apparently healthy elderly dogs.

ANIMALS

Hundred apparently healthy elderly dogs.

METHODS

Prospective study. Owners of 100 elderly dogs were asked to collect 2 free catch urine samples. Dogs were considered healthy based on owner's perception and an age chart, based on ideal bodyweight, was used to define dogs as senior or geriatric. UPC of urine collected by free catch and cystocentesis were compared. Overt proteinuria and borderline proteinuria were defined as UPC >0.5 and between 0.2 and 0.5, respectively, if examination of sediment did not explain proteinuria. Proteinuria was considered persistent if present at both sampling times.

RESULTS

At baseline, 71 owners succeeded in collecting urine. Eleven percent of dogs had overt proteinuria, 14% were borderline proteinuric, and 75% nonproteinuric. Thirty-seven repeated urine samples, with a median time interval of 31 days (range 10-90), were available. Nineteen percent of dogs had a persistently increased UPC (>0.2), with persistent overt proteinuria present in 8%. A strong correlation (ρ = 0.88) was found between UPC of urine collected by free catch and cystocentesis.

CONCLUSIONS AND CLINICAL IMPORTANCE

As 19% of study dogs had persistent proteinuria, our findings emphasize that measurement of proteinuria should be part of geriatric health screening. For UPC in dogs, free catch urine provides a good alternative to cystocentesis.

Laboratory tests for diagnosing and monitoring canine leishmaniasis

Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (increased acute phase proteins [APP] or α₂ - and/or γ-globulins). Although a potential gammopathy is usually polyclonal, it may also appear oligo- or monoclonal, especially in dogs coinfected by other vector-borne pathogens. When lesions are accessible to fine-needle aspiration (lymphoadenomegaly, nodular lesions, joint swelling), cytology is strongly advised, as the presence of Leishmania amastigotes in a pattern of pyogranulomatous inflammation or lymphoplasmacytic hyperplasia is diagnostic. If the cytologic pattern is inconclusive, the parasite should be identified by histology/immunohistochemistry or PCR on surgical biopsies. Alternatively, cytology and PCR may be performed on bone marrow samples where amastigotes, along with erythroid hypoplasia, myeloid hyperplasia, plasmacytosis, or secondary dysmyelopoiesis can be observed. Dogs with overt leishmaniasis generally have high antibody titers, while low titers predominate in immunologically resistant infected dogs or in exposed dogs with no parasite confirmation. Quantitative serology is recommended in clinically suspect dogs as high-titer antibodies titers may confirm the clinical diagnosis. In confirmed and treated dogs, renal function and inflammatory/immune response variables should be periodically monitored.

Measurement of proteinuria in dogs: analytic and diagnostic differences using 2 laboratory methods

BACKGROUND

Urinary protein-to-creatinine (UPC) ratio is an early diagnostic and prognostic marker of renal disease in dogs. Pyrogallol red molybdate (PRM) and Coomassie brilliant blue (CBB) are the most popular dye-binding assays for measurement of proteinuria. Published guidelines recommend strict cut-off points to substage patients with chronic renal diseases, irrespective of the assay applied. However, analytic variability and method-dependent differences could affect substaging of patients.

OBJECTIVES

The aims of this study were to analytically validate the CBB assay to evaluate possible method-dependent differences with PRM in urinary protein (UP) determination, and to assess the influence of such differences in substaging according to the International Renal Interest Society (IRIS).

METHODS

Urine was collected from healthy and proteinuric dogs. Intra-assay and inter-assay repeatability (imprecision), linearity under dilution (LUD), and spiking recovery (inaccuracy) were determined for the CBB assay. Split samples were measured with PRM and CBB, and agreement between methods and concordance in classification according to IRIS guidelines was determined.

RESULTS

The CBB assay was precise (< 10%) at all urine protein concentrations after excluding outliers from the intra-assay precision assay of high urine protein concentrations. Acceptable accuracy was demonstrated with both LUD and spiking recovery test. Both UP and UPC determined by CBB were significantly higher (P < .0001) than those obtained with PRM, and both a constant and proportional bias were present. Concordance of IRIS substaging was only moderate.

CONCLUSIONS

The CBB is precise and accurate, but the higher UPC obtained with CBB vs PRM may affect interpretation of the IRIS guidelines.

The effect of renal diet in association with enalapril or benazepril on proteinuria in dogs with proteinuric chronic kidney disease

Treating proteinuria in dogs reduces the progression of chronic kidney disease (CKD); renal diets and angiotensin-converting enzyme (ACE)-inhibitors are cornerstones of treatment. Whether different ACE-inhibitors have distinct kidney protective effects is unknown; it is therefore hypothesized that renal diets and enalapril or benazepril have different beneficial effects in proteinuric CKD dogs. Forty-four dogs with proteinuric CKD (IRIS stages 1-4) were enrolled in the study and were fed renal diet for 30 days. Thereafter, they were randomly assigned to one of 2 groups. Dogs in group A (n=22) received enalapril (0.5 mg/kg, q12h) and in group B (n=22) benazepril (0.5 mg/kg, q24h); in both groups, dogs were fed the same renal diet. After randomization, dogs were monitored for 120 days. Body weight and body condition score (BCS), serum concentrations of creatinine, blood urea nitrogen (BUN), albumin and total proteins, and urine protein-to-creatinine (UPC) ratio were compared at different time-points. After 30 days of renal diet, creatinine, BUN and UPC ratio decreased significantly (p<0.0001). Compared to randomization, body weight, BCS, albumin, total proteins, creatinine and BUN did not vary during follow-up in the 44 dogs and differences between group A and B were not observed. However, the UPC ratio of group A at day 60, 90 and 150 was significantly lower than in group B and compared to randomization (p<0.05). In group B it did not vary overtime. It is concluded that the renal diet is beneficial to decrease creatinine, BUN and UPC ratio in proteinuric CKD dogs. Enalapril further ameliorates proteinuria if administered along with renal diet.

Comparison between Urine Protein: Creatinine Ratios of Samples Obtained from Dogs in Home and Hospital Settings

Background

The urine protein:creatinine ratio (UPC) is used to quantify urine protein excretion and guide recommendations for monitoring and treatment of proteinuria.

Hypothesis/Objectives

Home urine samples will have lower UPCs than hospital samples. The objectives were to compare UPCs of samples collected in each setting and to determine whether environment of sample collection might affect staging, monitoring or treatment recommendations.

Animals

Twenty‐four client‐owned dogs.

Methods

Prospective, nonmasked study. Clients collected a urine sample from their dog at home and a second sample was collected at the hospital. Dogs receiving corticosteroids or angiotensin‐converting enzyme inhibitors were excluded, as were those with urine samples of inadequate volume, no protein on dipstick analysis, or active urine sediment. Samples were refrigerated after collection, dipstick and sediment evaluations were completed and each sample was frozen at −80°C within 12 hours. UPCs were performed on frozen samples within 2 months.

Results

From 81 paired samples, 57 were excluded. Of the remaining 24, 12/24 (50%) had higher hospital sample UPCs, 9/24 (38%) had identical UPCs, and 3/24 (12%) had lower hospital UPCs. The UPCs of hospital samples were higher than home samples for the total population (P = .005) and the subset with UPC > 0.5 (P = .001).

Conclusions

Setting and related circumstances of urine collection in dogs is associated with UPC differences; results are usually higher in hospital than in home samples. This difference has the potential to affect clinical interpretation.

Big-endothelin 1 (big ET-1) and homocysteine in the serum of dogs with chronic kidney disease

This study was aimed at determining the serum concentration of homocysteine (Hcy) and big endothelin-1 (big ET-1, the precursor of endothelin) in dogs with chronic kidney disease (CKD) with and without hypertension, proteinuria and inflammation, in order to explore their role as biomarkers of hypertension associated with CKD. Hcy and big ET-1 were measured using an enzyme-linked immunosorbent assay and an enzymatic cyclic reaction, respectively, in dogs with CKD staged, as proposed by the International Renal Interest Society (IRIS), using serum creatinine, urinary protein to creatinine (UPC) ratio and systolic blood pressure, and classified as affected or not by inflammation based on the serum concentration of C-reactive protein (CRP). Serum Hcy was significantly higher in dogs of IRIS stages II, III and IV compared with controls and in proteinuric compared with non-proteinuric dogs. No differences relating to the degree of hypertension or to the CRP concentration were found. Serum big ET-1 significantly increased in dogs of IRIS stage IV compared with controls, in proteinuric compared with non-proteinuric dogs, in dogs with severe hypertension compared with those without hypertension, and in dogs with increased CRP compared to those with normal CRP concentrations. Hcy only correlated with serum creatinine but big ET-1 significantly correlated with serum creatinine, UPC ratio, systolic blood pressure, and increased CRP. In conclusion, both Hcy and big ET-1 increase in dogs with CKD. Although further research is needed, big ET-1, but not Hcy, may also be considered as a biomarker of hypertension.

Proteinuria in canine patients with lymphoma

OBJECTIVES

To determine if proteinuria is more common in dogs with lymphoma when compared with healthy dogs and to assess the severity and frequency of proteinuria in dogs with lymphoma.

METHODS

Determination of urine protein:creatinine ratio in 32 dogs with lymphoma compared with 30 healthy dogs.

RESULTS

Canine patients with lymphoma are more likely to be proteinuric compared with healthy dogs. Proteinuria is common in dogs with lymphoma, although in most cases it is not severe. The presence of proteinuria is not linked with the stage or substage of lymphoma.

CLINICAL SIGNIFICANCE

Mild proteinuria is a common finding in dogs with lymphoma. The clinical impact of the proteinuria is probably low.