Relationship between thyroid function and sex hormones in female German shepherd dogs.

BACKGROUND: Several variables influence the serum concentration of thyroid hormones in dogs, including breed, age, drugs, and concurrent diseases. However, data regarding the interaction between thyroid function and the estrous stage of female dogs are limited. HYPOTHESIS: Estrous stage may influence thyroid function in German Shepherd dogs. METHODS: Longitudinal, observational, non-randomized cohort study. The dogs were monitored during the complete estrous cycle, and different stages were determined by vaginal cytology. Two blood samples were collected at the beginning and end of each stage to analyze the following: total thyroxine (TT4), free thyroxine (fT4), total triiodothyronine (TT3), free triiodothyronine (fT3), canine thyrotropin (cTSH), progesterone, 17-ß-estradiol, triglycerides, and cholesterol concentrations. Hematological and biochemical evaluations were performed at the beginning and end of the study period. ANIMALS: Seventeen German Shepherds were included, of which 7 were bred during the study period. One dog was excluded for estrus interruption and another for suspected hypothyroidism. RESULTS: Serum concentrations of T4, fT4, and fT3 were negatively correlated with age. Total thyroxine demonstrated significant changes in serum concentrations between estrous stages, with higher concentrations in estrus and diestrus. Total thyroxine concentrations were positively correlated with progesterone concentrations and negatively correlated with 17-ß-estradiol concentrations. Free thyroxine did not show significant variations but was positively correlated with progesterone concentrations. Canine TSH concentrations were positively correlated with 17-ß-estradiol concentrations. No significant differences in thyroid hormones and cTSH concentrations were observed between diestrus during pregnancy and pseudopregnancy. CONCLUSIONS: Different stages of estrus can influence the measurement of TT4 in female dogs.

Fecal Carriage of Extended-Spectrum ß-Lactamase-/AmpC-Producing Escherichia coli in Pet and Stray Cats.

Dogs have been reported as potential carriers of antimicrobial-resistant bacteria, but the role of cats has been poorly studied. The aim of this study was to investigate the presence and the risk factors associated with the fecal carriage of extended-spectrum ß-lactamase and AmpC (ESBL/AmpC)-producing Escherichia coli (E. coli) in pet and stray cats. Fecal samples were collected between 2020 and 2022 from healthy and unhealthy cats and screened for ESBL/AmpC-producing E. coli using selective media. The presence of ESBL/AmpC-producing E. coli was confirmed by phenotypic and molecular methods. The evaluation of minimum inhibitory concentrations (MICs) was performed on positive isolates. Host and hospitalization data were analyzed to identify risk factors. A total of 97 cats' samples were collected, and ESBL/AmpC-producing E. coli were detected in 6/97 (6.2%), supported by the detection of blaCTX-M (100%), blaTEM (83.3%), and blaSHV (16.7%) genes and the overexpression of chromosomal ampC (1%). All E. coli isolates were categorized as multidrug-resistant. Unhealthy status and previous antibiotic therapy were significantly associated with ESBL/AmpC-producing E. coli fecal carriage. Our results suggest that cats may be carriers of ESBL/AmpC-producing E. coli, highlighting the need for antimicrobial stewardship in veterinary medicine and an antimicrobial-resistance surveillance program focusing on companion animals, including stray cats.

Nutritional secondary hyperparathyroidism in a kitten, supported by immunoenzymatic measurement of feline intact parathyroid hormone.

A 6-mo-old, intact male, domestic shorthair cat was referred with a history of poor growth, reluctance to move, and deformation of the nasal profile. The kitten had been fed a diet composed almost exclusively of a complementary pet food and tuna, which was similar to an all-meat diet. We detected osteopenia and hypocalcemia associated with severe parathyroid hormone (PTH) and calcitriol increases; we measured PTH concentrations with an immunoenzymatic method that has been validated in cats. Dietary correction, consisting of a complete and balanced wet pet food formulated for growth, resulted in normalization of calcium and PTH concentrations within 2 mo.

Comparison of six microscopic methods and two operators for estimation of white and red blood cells in canine urine sediment.

BACKGROUND: Little information is currently available about the analytical variability of urinalysis. OBJECTIVE: We aimed to compare results obtained by two operators using six microscopic methods in the quantification of urinary leukocytes (WBC) and erythrocytes (RBC). METHODS: Forty urine samples (10 mL) were centrifuged (450g, 5 minutes) and resuspended in 0.5 mL of supernatant. Two operators with different expertise in urinalysis interpreted sediment results using the six methods, obtained by combining the use of microscope slides (Slide) or counting chambers (Chamber) with three different techniques: bright-field (BF) microscopy, phase-contrast (PC) microscopy, and stained sediment (SS) evaluations. The mean WBC and RBC counts from 10 fields (Slide) or squares (Chamber) observed at 400× were used to calculate the difference and agreement between operators and methods. We also estimated the concordance between methods in classifying microhematuric or pyuric samples. RESULTS: Operator 2 counted significantly lower WBC counts using Slide+BF (P = 0.009) and Slide+PC (P = 0.001) than Operator 1, whereas no inter-operator differences were recorded for RBC counts. The concordance between the operators ranged from "good" to "very good." No differences or biases were found for WBC counts among the methods, and concordances were "good" to "very good"; proportional biases were found for RBC counts between Slide+BF vs Slide+SS and Slide+PC vs Slide+SS. Concordance measurements for RBC counts ranged from "good" to "very good." CONCLUSIONS: All methods yielded good reproducibility among operators, although stained SS evaluations allowed better identification of WBC by the inexperienced operator. However, we suspected that the SS preparations affected RBC counts. All other methods yielded reproducible WBC and RBC counts.

Ovarian Neuroglial Choristoma in a Bitch.

Neuroglial choristomas are rare malformations consisting of heterotopic mature neural tissue at a site isolated from the brain or spinal cord. In human medicine, neuroglial choristomas are predominantly reported in the head and in the neck, except for one recent case reported in a foot of a child. In domestic animals, neuroglial choristomas are exceedingly rare, reported only in the retina of a dog, in the pharynx and in the skin of two kittens, and within the oropharynx of a harbor seal. A three-year-old intact female Jack Russell Terrier presented for elective ovariectomy exhibited a cystic lesion 2 cm in diameter expanding in the right ovary. Histological examination of the lesion revealed a mass composed of well-organized neuroglial tissue. Immunohistochemistry with primary antibodies against GFAP, NSE, and IBA-1 confirmed the neuroglial origin of the mass. At the time of this writing, 7 years after ovariectomy, the dog was clinically normal. Together with a recent case described in the foot of a child, this case confirms that neuroglial choristoma may also be found far from the skull or spine, supporting the hypothesis that they may arise from an early embryological migration defect.

Analytical Validation of a New Immunoenzymatic Method for the Measurement of Feline Parathyroid Hormone in Cats with Chronic Kidney Disease.

The determination of parathyroid hormone (PTH) in cats could be of clinical utility in many metabolic disorders, such as renal diseases, hypercalcemia, or nutritional imbalances. However, the available methods for the measurement of feline PTH are limited, not widely available, and need radioimmunoassays. The aim of this study was to perform the analytical validation of a new immunoenzymatic method for the measurement of feline PTH. Thirty-eight cats affected with chronic kidney disease (CKD) were included. PTH was measured using a two-site immunoenzymatic method validated in humans and dogs (ST AIA-PACK® Intact PTH, Tosoh Bioscience, Tessenderlo, Belgium). The analytical validation provided the evaluation of precision (intra-assay and inter-assay), accuracy (linearity under dilution (LUD) and spike recovery test (SRT)), and the storage stability of serum samples at 20 °C, 4 °C, and -20 °C. The method showed good precision (intra-assay CVs (coefficient of variations) 3.19-9.61%; inter-assay CVs 9.26-15.28%). In both the intra- and inter-assays, the highest imprecision was found with the low concentration pool (9.61% and 15.28%) and accuracy (LUD and SRT r2 = 0.99, p < 0.001), while the stability was optimal up until 7 days at -20 °C (-7.7%). The method was successfully validated in cats, allowing its future use in diagnostic procedures.

Influence of preanalytical factors on feline proteinuria.

BACKGROUND: To date, little information is available about the effect of preanalytical factors on the urinary protein-to-creatinine (UPC) ratio in cats. OBJECTIVES: We aimed to evaluate the effect of a commercially available cat litter, creatinine measurements at three different dilutions of urine, and different storage conditions on the UPC ratio in cats. METHODS: Feline urine specimens were prospectively collected. Twenty-two whole-urine specimens were placed uncovered and in contact with cat litter for 1 hour; 25 urine supernatants were diluted 1:10, 1:20, and 1:100 for creatinine measurements. The correlation, difference, agreement, and concordance in classifying specimens according to International Renal Interest Society staging were determined. Storage effects on UPC ratios were assessed in specimens stored for 6 hours at +20℃ (n = 20), 1 week at +4℃ (n = 20), and 3 months at -20℃ (n = 25). Specimens were also subjected to four freeze-thaw cycles (n = 20). Results were compared, and clinical significance was assessed by comparing each UPC ratio to the inter-assay range of the baseline value. RESULTS: Exposure to cat litter did not affect UPC ratios. A positive proportional bias was found in the 1:100 dilution compared with the 1:20 dilution; however, concordance was high for all comparisons. At +20, +4℃, and after four repeated freeze-thaw cycles, UPC ratios were stable. Compared with baseline values, UPC ratios decreased (P < .01) after 8 and 12 weeks at -20℃. However, all UPC ratios were within the inter-assay variability of the baseline value. CONCLUSIONS: Exposure to cat litter did not affect UPC ratios, but further studies are necessary to evaluate other potential variables. The effects of the dilutions and storage conditions were clinically acceptable, although the 1:20 and 1:100 dilutions were not perfectly comparable.

Urinary tract infection by atypical uropathogens in dogs.

Bacterial urinary tract infection (UTI) is a common condition affecting dogs. Urine culture and antimicrobial susceptibility test, associated with the identification of underlying cause, are of primary importance in order to select a correct treatment, especially in presence of comorbidities. Two cases of immunecompromised dogs affected by urinary tract infection (UTI) have been described: the first, probably immunosuppressed due to old age, was in poor body condition, with severe odontolithiasis and periodontitis; the second was affected by chronic kidney disease in advanced stage. Urine cultures isolated two rare and atypical pathogens, Moellerella wisconsensis and Brevundimonas vesicularis, both showing sensitivity versus floroquinolones which were selected for the treatment. After a 4 weeks treatment, a second culture demonstrated the resolution of infection in both cases, in absence of clinical signs.To date neither of the two bacteria have been reported as cause of UTI in dog.

Population Pharmacokinetic Model of Iohexol in Dogs to Estimate Glomerular Filtration Rate and Optimize Sampling Time.

Monitoring iohexol plasma clearance is considered a useful, reliable, and sensitive tool to establish glomerular filtration rate (GFR) and early stages of kidney disease in both humans and veterinary medicine. The assessment of GFR based on iohexol plasma clearance needs repeated blood sampling over hours, which is not easily attainable in a clinical setting. The study aimed to build a population pharmacokinetic (Pop PK) model to estimate iohexol plasma clearance in a population of dogs and based on this model, to indicate the best sampling times that enable a precise clearance estimation using a low number of samples. A Pop PK model was developed based on 5 iohexol plasma samples taken from 5 to 180 minutes (min) after an intravenous iohexol nominal dose of 64.7 mg/kg from 49 client-owned dogs of different breeds, sexes, ages, body weights, and clinical conditions (healthy or presenting chronic kidney disease CKD). The design of the best sampling times could contain either 1 or 2 or 3 sampling times. These were discretized with a step of 30 min between 30 and 180 min. A two-compartment Pop PK model best fitted the data; creatinine and kidney status were the covariates included in the model to explain a part of clearance variability. When 1 sample was available, 90 or 120 min were the best sampling times to assess clearance for healthy dogs with a low creatinine value. Whereas for dogs with CKD and medium creatinine value, the best sampling time was 150 or 180 min, for CKD dogs with a high creatinine value, it was 180 min. If 2 or 3 samples were available, several sampling times were possible. The method to define the best sampling times could be used with other Pop PK models as long as it is representative of the patient population and once the model is built, the use of individualized sampling times for each patient allows to precisely estimate the GFR.

Analytical and Clinical Validation of a New Immunoenzymatic Method for the Measurement of Canine Parathyroid Hormone.

Renal hyperparathyroidism (RHPT) is one of the main complications in dogs affected with Chronic Kidney Disease (CKD). The measurement of serum parathyroid hormone (PTH) could be of clinical utility for the disease's treatment and follow-up; however, PTH is not routinely determined due to limited available methods, often not fully validated in dogs. The aims of this study were the analytical validation of an immunoenzymatic method for the measurement of PTH in canine serum and the analysis of preliminary association of the obtained results with renal function. Twenty-six samples obtained from dogs healthy or affected with CKD were analysed. PTH was measured using a two-site immunoenzymometric human assay (ST AIA-PACK® Intact PTH, Tosoh Bioscience). The analytical validation protocol evaluated the assay precision and accuracy. Also, the PTH's storage stability at 20 °C, 4 °C and -20 °C was assessed. Clinical validation was performed by comparing PTH values with creatinine, phosphorus and International Renal Interest Society (IRIS) stage. The method showed optimal precision and accuracy, whereas stability was adequate up to 4 h at 20 °C, 24 h at 4 °C and 6 months at -20 °C. PTH was positively associated with creatinine, phosphorus and IRIS stage. The investigated method was thus successfully validated in dogs, allowing its use for clinical purpose.

Evaluation of Urinary Big Endothelin-1 in Feline Spontaneous CKD.

The endothelin-1 (ET-1) system has been implicated in the development and progression of chronic kidney disease (CKD). No information on big ET-1 in feline urine is available. The purpose of this study was to evaluate if urinary big endothelin-1 (bigET-1) is associated with feline CKD. Sixty urine samples were prospectively collected from 13 healthy cats at risk of developing CKD and 22 cats with CKD of different International Renal Interest Society (IRIS) stages (1-4). Urinary bigET-1 was measured using a commercially available ELISA. BigET-1 normalized to urine creatinine (bigET-1:UC) was compared amongst stages and substages, as proposed by IRIS, and correlated with serum creatinine concentration, proteinuria and blood pressure. BigET-1:UC at the time of inclusion was compared between cats that remained stable and cats that progressed after 12 months. BigET-1:UC was significantly higher (p = 0.002) in cats at IRIS stages 3-4 (median: 21.9; range: 1.88-55.6), compared to all other stages, and in proteinuric (n = 8, median: 11.0; range: 0.00-46.4) compared with nonproteinuric cats (n = 38 median: 0.33; range: 0.00-55.6) (p = 0.029). BigET-1:UC was not associated with CKD progression. Urinary bigET-1 increased in advanced stages of CKD and in proteinuric patients, suggesting that ET-1 may be indicative of the severity of feline CKD.

Haematological and biochemical reference intervals in healthy racing and retired Italian Greyhounds.

In view of the enormous variability of dog breeds, breed-specific reference intervals (RIs) are recommended for use in veterinary clinical decision-making. The aim of this study was to determine whether RIs of the general canine population may be applied to the Italian Greyhound (Piccoli Levrieri Italiani or PLI), and to generate breed-specific RIs, where appropriate. Sixty-three privately owned clinically healthy fasted dogs were examined. Routine haematology and biochemistry were performed on 58 enrolled patients using the ADVIA 120 haematology analyzer and the Cobas Mira system, respectively. Changes in haematological and biochemical parameters depending on sex, age and attitude (resting vs. running dogs) were investigated. The results of PLI were compared with the RIs of the general canine population. In those cases in which these RIs were not validated, new RIs were generated according to the guidelines of the American Society of Veterinary Clinical Pathology. Pre-existing RIs were considered valid based on the recommendations by the Clinical & Laboratory Standards Institute (CLSI). RIs were higher for mean corpuscular haemoglobin (MCH), mean cell haemoglobin concentration (MCHC), cell haemoglobin concentration mean (CHCM) and lower for large unstained cells (LUC). A wider discrepancy between pre-existing and newly established RIs was found for some ADVIA parameters regarding red blood cell (RBC) or reticulocyte morphology. For total protein and cholesterol the new RIs were wider than the pre-existing ones, while albumin, calcium and iron were higher. This study suggests that most of the RIs published in veterinary textbooks cannot be validated for PLIs.

Electrophoretic patterns of proteinuria in feline spontaneous chronic kidney disease.

OBJECTIVES: The purpose of this study was to describe the electrophoretic patterns of proteinuria in cats at risk of and cats with chronic kidney disease (CKD), and to investigate whether the presence of high-molecular-weight (HMW) and low-molecular-weight (LMW) proteins were associated with CKD, proteinuria and/or disease progression. METHODS: Healthy cats at risk of developing renal disease (n = 17) and cats affected with CKD at different stages (n = 22) were prospectively enrolled and sampled over time. Seventy urine samples were included and assayed with a commercially available sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE) method. Each sample (gel lane) was inspected to identify albumin, HMW and LMW proteins, and an electrophoretic pattern (albuminuria, glomerular, tubular, mixed or negative) was assigned accordingly. Fisher's exact test was used to assess the distribution of HMW and LMW proteins in cats grouped according to International Renal Interest Society stage and to the magnitude of proteinuria, and to assess if HMW and LMW proteins at the time of inclusion were associated with the development and progression of CKD. RESULTS: In samples of cats at risk, the most common pattern was glomerular (84.6%); glomerular pattern was also common in cats with CKD (54.2%), although mixed proteinuria and tubular proteinuria were also present (29.5% and 11.4%, respectively). The presence of LMW proteins was associated with CKD (P <0.0001) and to a urine protein:creatinine ratio >0.2 (P = 0.025). Both HMW and LMW proteins were not associated with progression of CKD within 6 months (n = 14). CONCLUSIONS AND RELEVANCE: Our results showed that HMW proteinuria is common in healthy cats at risk of developing CKD, although the pathological significance needs to be confirmed. The detection of LMW proteins in urine of cats suspected to be affected by CKD, especially in non-azotaemic, non-proteinuric or borderline proteinuric cats, suggests the presence of kidney damage.

Diagnostic potential of simplified methods for measuring glomerular filtration rate to detect chronic kidney disease in dogs.

BACKGROUND: Glomerular filtration rate (GFR) is the most sensitive indicator of initial renal function decline during chronic kidney disease (CKD), but conventional protocols for measuring GFR are labor-intensive and stressful for the dog. OBJECTIVES: To assess the diagnostic potential for detecting CKD with simplified GFR protocols based on iohexol plasma clearance. ANIMALS: Seventeen CKD-positive and 23 CKD-negative dogs of different breeds and sex. METHODS: Prospective nonrandomized study. Plasma iohexol was measured 5, 15, 60, 90, and 180 minutes after injection. Glomerular filtration rate was calculated using 5 samples (GFR5 ) or simplified protocols based on 1, 2, or 3 samples. The GFR5 and simplified GFR were compared by Bland-Altmann and concordance correlation coefficient (CCC) analysis, and diagnostic accuracy for CKD by receiver operating characteristic curves. A gray zone for each protocol was bounded by the fourth quartile of the CKD-positive population (lower cutoff) and the first quartile of the CKD-negative population (upper cutoff). RESULTS: All simplified protocols gave reliable GFR measurements, comparable to reference GFR5 (CCC >0.92). Simplified protocols which included the 180-minutes sampling granted the best GFR measure (CCC: 0.98), with strong diagnostic potential for CKD (area under the receiver operating characteristic curve ± SE: 0.98 ± 0.01). A double cutoff including a zone of CKD uncertainty guaranteed reliable diagnosis outside the gray area and identified borderline dogs inside it. CONCLUSIONS: The simplified GFR protocols offer an accurate, hands-on tool for CKD diagnosis in dogs. The gray zone might help decision-making in the management of early kidney dysfunction.

Hematologic and biochemical reference intervals in Shetland Sheepdogs.

BACKGROUND: Several breeds have physiological peculiarities that induce variations in reference intervals (RIs) compared with the general canine population. Shetland sheepdogs (SSs) are reported to be more predisposed to different diseases (eg, hyperlipidemia, gallbladder mucocele, and hypothyroidism). Consequently, a breed-specific approach is more often required. OBJECTIVES: The aim of this study was to determine whether the RIs of the general canine population could be applied to that of SSs, and to generate breed-specific RIs, where appropriate. METHODS: Sixty clinically healthy and fasted SSs (36% of the population registered at the Italian Breed association) were examined. Routine hematology and biochemistry analyses were performed. The transference method was used to compare the results of SSs with the RIs of the general canine population. When these RIs were not validated, new RIs were generated according to the guidelines of the American Society of Veterinary Clinical Pathology. Differences associated with sex, age, coat color, and whether used as a pet, a herding dog, or an agility dog were also investigated. RESULTS: The transference method validated for 30/38 SS RIs. For 6 of the remaining 8 variables, the difference with the claimed RIs could depend on preanalytical or analytical artifacts, whereas for glucose and total cholesterol, these differences could depend on breed peculiarities. However, in all SSs, the concentration of cholesterol was <12.95 mmol/L. Relevant differences associated with sex, age, coat color, and use were not found. CONCLUSIONS: This study suggests that breed-specific RIs should be used for glucose and cholesterol in SSs.

Evaluation of the analytical variability of urine protein-to-creatinine ratio in cats.

BACKGROUND: Proteinuria quantification with the urinary protein-to-creatinine (UPC) ratio is part of the diagnostic process in feline patients suspected of chronic kidney disease (CKD). In affected cats, monitoring and substaging of the UPC according to the International Renal Interest Society (IRIS) guidelines is also necessary for appropriate patient management. No information is available about the possible effects of analytical variability on urinary proteins (UPs) and the UPC ratio in cats. OBJECTIVES: This study aimed to determine whether imprecision and method-dependent differences due to the two dye-binding methods, pyrogallol red-molybdate (PRM) and Coomassie brilliant blue (CBB), could affect IRIS substaging. METHODS: Urine samples were collected from proteinuric and nonproteinuric cats. Intra-assay and inter-assay repeatability were assessed with both the PRM and CBB methods. Urinary supernatants (n = 120) were tested using both methods. Agreement between the methods and concordance with sample classification according to IRIS guidelines were determined. RESULTS: On average, the PRM method yielded a higher CV (UP 8.4 ± 5.2%; UPC 9.5 ± 4.8%) than the CBB method (UP 5.6 ± 2.6%; UPC 7.2 ± 2.6%), but similar rates of misclassification were found in samples with UPC ratios close to the IRIS cut-off. Although the two methods were correlated, the CBB method tended to yield UPs and UPC ratios that were significantly higher (P < 0.0001) than that of the PRM method. The Passing-Bablok test also found constant and proportional errors between the PRM and CBB methods. Concordance in substaging samples according to IRIS was good (k coefficient = 0.62). CONCLUSIONS: The two methods were precise, but the higher UPC ratios obtained with the CBB methods might affect the interpretation using the IRIS guidelines and clinical decisions.

Association of amniotic uric acid, glucose, lactate and creatinine concentrations and lactate/creatinine ratio with newborn survival in small-sized dogs - preliminary results.

In order to define the normal composition of canine amniotic fluid and to detect differences between surviving and non-surviving newborn puppies, the present study determined the uric acid, glucose, lactate and creatinine concentrations and the lactate to creatinine ratio in amniotic fluids collected during elective Caesarean section from small-sized purebred bitches. The possible relationship between newborn survival and the studied parameters, as well as the effects of maternal parity, fetal gender and Apgar score were assessed. The study enrolled 27 small-sized purebred bitches submitted to elective Caesarean section at term. After opening the fetal membranes, amniotic fluid samples were collected aseptically from the amniotic sac of each fetus. The data obtained from 74 amniotic fluid samples collected from 27 bitches showed that amniotic glucose concentration was lower (P < 0.05) in non-surviving than in surviving puppies. Within the normal, surviving puppies, amniotic glucose concentration was higher (P < 0.05) in male than in female newborns, and the lactate/creatinine ratio was significantly higher in multiparous than in primiparous bitches (P < 0.05). These preliminary results demonstrate the relevance of amniotic glucose, but not of uric acid, lactate, creatinine and the lactate to creatinine ratio for detecting puppies at risk of death immediately after birth.

Serum symmetric dimethylarginine and creatinine in Birman cats compared with cats of other breeds.

Objectives The aim of this study was to assess whether, in contrast to serum creatinine, which is higher in Birman cats than in other breeds, the serum concentration of symmetric dimethylarginine (SDMA) is comparable in clinically healthy Birmans and in the general feline population. This could allow, in this breed, to better evaluate chronic kidney disease (CKD). Methods Serum creatinine and SDMA were measured in clinically healthy Birmans (n = 50) and in cats of other breeds (n = 46), and the results were statistically compared. A breed-specific reference interval (RI) was established for Birmans and compared with the RI for the general feline population (0.0-14.0 µg/dl). Results Creatinine (1.58 ± 0.36 mg/dl) and SDMA (12.2 ± 2.8 µg/dl) were higher ( P <0.001) in Birmans than in cats of other breeds (1.19 ± 0.17 mg/dl; 10.3 ± 2.5 µg/dl). In 20/50 Birman cats (40.0%) serum creatinine was higher than both the non-breed-specific RI of our laboratory and the threshold recommended to classify cats as IRIS stage 2 (1.6 mg/dl). The concentration of SDMA was higher than the pre-existing RI in 10/50 Birmans (20.0%) and in four cats of other breeds (8.7%). Among Birmans, the proportion of cats with SDMA >14 µg/dl was lower ( P <0.017) than the proportion of cats with creatinine >1.60 mg/dl. However, the deviation from the upper limit of the RI was lower than the analytical variability of the method in 7/10 Birmans and in 4/4 cats of other breeds. The breed-specific RI (3.5-18.7 µg/dl) overlapped with the pre-existing one. Conclusions and relevance SDMA may be a better marker of CKD in Birman cats than creatinine when non-breed-specific RIs are utilised. The coupled analysis of creatinine and SDMA could help prevent errors in diagnosing and staging CKD in Birman cats.

Sensitivity and specificity of manual and automated measurements of reticulocyte parameters for classification of anemia in dogs: 174 cases (1993-2013).

OBJECTIVE To assess sensitivity and specificity of manual and automated measurements of reticulocyte percentage, number, and production index for classification of anemia in dogs. DESIGN Retrospective case series SAMPLE 174 blood smears from client-owned dogs with anemia collected between 1993 and 2013 for which reticulocyte parameters were determined manually (nonregenerative anemia, 22; preregenerative anemia, 23; regenerative anemia, 28) or with an automated laser-based counter (nonregenerative anemia, 66; preregenerative anemia, 17; regenerative anemia, 18). PROCEDURES Diagnostic performance was evaluated with receiver operating characteristic (ROC) curves by considering preregenerative anemia as nonregenerative or regenerative. Sensitivity, specificity, and positive likelihood ratio were calculated by use of cutoffs determined from ROC curves or published reference limits. RESULTS Considering preregenerative anemia as non regenerative, areas under the curve (AUCs) for reticulocyte percentage, number, and production index were 97%, 93%, and 91% for manual counting and 93%, 90%, and 93% for automated counting. Sensitivity, specificity, and positive likelihood ratio were 82% to 86%, 82% to 87%, and 4.6 to 6.4, respectively. Considering preregenerative anemia as regenerative, AUCs were 77%, 82%, and 80% for manual counting and 81%, 82%, and 92% for automated counting. Sensitivity, specificity, and positive likelihood ratio were 72% to 74%, 76 to 87%, and 2.7 to 6.2, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Whereas all reticulocyte parameters identified regeneration in anemic dogs, the performance of specific parameters was dependent on the method used. Findings suggested that lower cutoffs than published reference limits are preferred for reticulocyte number and production index and higher cutoffs are preferred for reticulocyte percentage. Reticulocyte production index may be useful when the pretest probability of regeneration is moderate.