Accuracy of urine dipstick tests and urine glucose-to-creatinine ratios for assessment of glucosuria in dogs and cats.

OBJECTIVE: To assess the accuracy of automated readings of urine dipstick results for assessment of glucosuria in dogs and cats, compare visual versus automated readings of urine glucose concentration, and determine the utility of the urine glucose-to-creatinine ratio (UGCR) for quantification of glucosuria. SAMPLE: 310 canine and 279 feline urine samples. PROCEDURES: Glucose concentration was estimated in 271 canine and 254 feline urine samples by visual assessment of urine dipstick results and with an automated dipstick reader. Absolute urine glucose and creatinine concentrations were measured in 39 canine and 25 feline urine samples by colorimetric assay with a clinical chemistry analyzer (reference standard for detection of glucosuria), and UGCRs were determined. RESULTS: Automated assessment of the urine dipsticks yielded accurate results for 163 (60.1%) canine urine samples and 234 (92.1%) feline urine samples. Sensitivity of the automated dipstick reader for detection of glucosuria was 23% for canine samples and 68% for feline samples; specificity was 99% and 98%, respectively. Visual readings were more accurate than automated readings for both canine and feline urine. The UGCR was significantly correlated with absolute urine glucose concentration for both dogs and cats, yet there was incomplete distinction between dipstick categories for glucose concentration and UGCR. CONCLUSIONS AND CLINICAL RELEVANCE: Urine dipstick readings for dogs and cats were useful for ruling glucosuria in when the result was positive but not for ruling it out when the result was negative. The evaluated dipsticks were more accurate for detection of glucosuria in cats than in dogs. Visual dipstick readings were more accurate than automated readings. The UGCR did not appear to provide additional useful information.

Effect of blood contamination on results of dipstick evaluation and urine protein-to-urine creatinine ratio for urine samples from dogs and cats.

OBJECTIVE To evaluate effects of blood contamination on dipstick results, specific gravity (SG), and urine protein-to-urine creatinine ratio (UPCR) for urine samples from dogs and cats. SAMPLE Urine samples collected from 279 dogs and 120 cats. PROCEDURES Urine pools were made for each species (dogs [n = 60] and cats [30]). Blood was added to an aliquot of a pool, and serial dilutions were prepared with the remaining urine. Color and dipstick variables were recorded, and SG and UPCR were measured. For cats, 1 set of pools was used; for dogs, 2 sets were used. Comparisons were made between undiluted urine and spiked urine samples for individual colors. Repeated-measures ANOVA on ranks was used to compare dipstick scores and UPCR results; χ2 tests were used to compare proteinuria categorizations (nonproteinuric, borderline, or proteinuric). RESULTS Any blood in the urine resulted in significantly increased dipstick scores for blood. In both species, scores for bilirubin and ketones, pH, and SG were affected by visible blood contamination. No significant difference for the dipstick protein reagent results was evident until a sample was visibly hematuric. The UPCR was significantly increased in dark yellow samples of both species. Proteinuria categorizations differed significantly between undiluted urine and urine of all colors, except light yellow. CONCLUSIONS AND CLINICAL RELEVANCE Any degree of blood contamination affected results of dipstick analysis. Effects depended on urine color and the variable measured. Microscopic blood contamination may affect the UPCR; thus, blood contamination may be a differential diagnosis for proteinuria in yellow urine samples.

Effect of heartworm disease and heartworm-associated respiratory disease (HARD) on the right ventricle of cats.

BACKGROUND: Dirofilaria immitis infection occurs in dogs and cats, both of which species are clinically affected by mature adult infections. Cats are uniquely affected by immature-adult infections with an inflammatory pulmonary disease called Heartworm-Associated Respiratory Disease (HARD). D. immitis infection causes pulmonary parenchymal and vascular pathology in the dog and cat. Dogs develop pulmonary hypertension and cor pulmonale, whereas the development of pulmonary hypertension is rare in the cat. D. immitis infection in the dog causes alteration of the right ventricular (RV) extracellular matrix, including a decrease in myocardial collagen. In this study, the RV myocardial changes of cats infected with adult and immature-adult D. immitis were assessed. METHODS: The cardiopulmonary systems of six groups of SPF cats (n = 9-10 per group) were examined 8 or 18 months after infection with L3 D. immitis. Two groups were untreated and allowed to develop adult HW; two groups were treated with ivermectin starting 3 months post infection, thus allowing HARD but no mature adult heartworms; and two groups were treated with selamectin beginning 1 month post infection, preventing development of L5 or adult heartworms. A group of specific pathogen free (SPF) normal cats was utilized as a negative control (n = 12). Lung pathologic lesions were objectively assessed, and both RV and left ventricular (LV) weights were obtained to calculate an RV/LV ratio. Intramural RV myocardial collagen content was quantitatively assessed. RESULTS: RV/LV weight ratios were not different between groups. Negative control cats had significantly greater RV collagen content than all other affected groups (P = 0.032). Analysis of the RV/LV ratios and collagen content revealed no significant relationship (r = 0.03, P = 0.723, respectively). Collagen content had a modest, but significant, negative correlation, however, with both pulmonary vascular pathology (r = -0.25, P = 0.032) as well as the total pulmonary parenchymal and vascular pathology (r = -0.26, P = 0.025). CONCLUSIONS: Cats infected with mature and immature D. immitis did not develop RV hypertrophy but did demonstrate loss of RV myocardial collagen content. The collagen loss was present at 8 and 18 months after infection in all infected cats. This loss of RV myocardial collagen was correlated with the severity of pulmonary parenchymal and vascular pathology.

Automated in-clinic hematology instruments for small animal practitioners: what is available, what can they really do, and how do i make a choice?

The decision to purchase an in-office hematology instrument is typically based on the desire to have immediate access to complete blood count (CBC) data for disease diagnosis and follow-up and perhaps add to the financial bottom line of your practice. The decision regarding which in-office hematology instrument to purchase requires comparison of available instruments, how they function and knowledge of their strengths and limitations, what analytes they report, their ease of use, and their initial and continued costs. Other considerations include instrument space requirements, ability to interact with your existing data management system, the methods used by analyzers, and data accuracy.

Botryoid nuclei in the peripheral blood of a dog with heatstroke.

An EDTA-anticoagulated blood sample collected from a 1.5-year-old, intact male, English Bulldog was submitted for a CBC. The CBC data and blood smear evaluation revealed borderline high hematocrit (54%, reference interval 37-55%), inappropriate rubricytosis, moderate leukopenia due to both mature neutropenia and lymphopenia, and mild thrombocytopenia. Numerous leukocytes showed evidence of karyolysis, pyknosis, and karyorhexis, and apoptotic bodies were frequent in the background. Many neutrophils had botryoid nuclei characterized by increased numbers of nuclear segments radially arranged with spoke-like, delicate chromatin filaments connecting the segments centrally. The finding of botryoid nuclei and inappropriate rubricytosis was indicative of severe hyperthermia, such as heatstroke. The dog had been exercised a long time during conditions of high temperature and humidity until he collapsed. The dog was diagnosed with severe heatstroke, hypovolemic shock, disseminated intravascular coagulation, and multiorgan dysfunction syndrome. Despite aggressive treatment, the patient died of cardiopulmonary arrest. Botryoid nuclei are frequent in people with heatstroke. In the authors' experience, botryoid nuclei are seen commonly in dogs with heatstroke, but they have never been reported in veterinary medicine. The presence of petechiation with only mild thrombocytopenia and inappropriate rubricytosis also is suggestive of heatstroke and manifests ongoing life-threatening vascular derangement.

Seroprevalence of Ehrlichia canis, Ehrlichia chaffeensis and Ehrlichia ewingii in dogs in North America.

BACKGROUND: This study evaluated the exposure of dogs to three different Ehrlichia spp. in the south and central regions of the United States where vector-borne disease prevalence has been previously difficult to ascertain, particularly beyond the metropolitan areas. METHODS: Dog blood samples (n = 8,662) were submitted from 14 veterinary colleges, 6 private veterinary practices and 4 diagnostic laboratories across this region. Samples were tested for E. canis, E. chaffeensis and E. ewingii specific antibodies using peptide microtiter ELISAs. RESULTS: Overall, E. canis, E. chaffeensis and E. ewingii seroprevalence was 0.8%, 2.8%, and 5.1%, respectively. The highest E. canis seroprevalence (2.3%) was found in a region encompassing Arkansas, Louisiana, Oklahoma, Tennessee and Texas. E. chaffeensis seroreactivity was 6.6% in the central region (Arkansas, Kansas, Missouri, and Oklahoma) and 4.6% in the southeast region (Georgia, Maryland, North Carolina, South Carolina, Tennessee and Virginia). Seroreactivity to E. ewingii was also highest in the central region (14.6%) followed by the southeast region (5.9%). The geospatial pattern derived from E. chaffeensis and E. ewingii seropositive samples was similar to previous reports based on E. chaffeensis seroreactivity in white-tailed deer and the distribution of human monocytic ehrlichiosis (HME) cases reported by the CDC. CONCLUSIONS: The results of this study provide the first large scale regional documentation of exposure to E. canis, E. chaffeensis and E. ewingii in pet dogs, highlighting regional differences in seroprevalence and providing the basis for heightened awareness of these emerging vector-borne pathogens by veterinarians and public health agencies.

Automated in-clinic hematology instruments for small animal practitioners: what is available, what can they really do, and how do i make a choice?

To have an in-clinic hematology instrument in your practice and how it is used are decisions that precede the purchase of an instrument. Advantages and limitations of the various instruments should be considered. Initial purchase cost, reagent/disposable costs, costs of training personnel in the use and care of the instrument, and service/repair contract costs need to be considered. Once the decision is made to have an in-office hematology instrument in your practice you should benefit from having nearly immediate CBC data results that enable you to provide better quality medicine, more rapid clinical decisions, more closely monitor patients for complications of disease or response to treatment. It should also generate revenue and allow some of your staff members to expand and develop their technical skills as they learn the nuances of a new diagnostic tool and how to provide you with the most accurate CBC information. In the final assessment, the addition of an in-office hematology instrument should improve the quality and efficiency of the medical care you provide patients and generate additional practice income.

Glucose detection and concentration estimation in feline urine samples with the Bayer Multistix and Purina Glucotest.

The Bayer Multistix are commonly used for detection and estimation of feline glucosuria by veterinarians and cat owners. A newer product, the Purina Glucotest, utilizes the same enzymatic technology for detection of glucose, but has been designed for home use as a litter additive that allows interpretation of glucosuria over an 8-h period. The objectives of this study were to assess the sensitivity, specificity, and accuracy of the Glucotest and Multistix, and to assess the 8-h color stability of the Glucotest. Overall, the Glucotest had greater sensitivity and specificity than the Multistix, and more accurately estimated urine glucose concentration if evaluated at least 30 min after exposure to urine. A significant lack of agreement between the results obtained immediately after exposure to urine vs after 30 min and 8 h contradicts the 8-h color stability claim, but the change in urine glucose concentration estimation over time resulted in improved test accuracy at the 30 and 480 min time points.

Multimodal treatment of recurrent sinonasal cryptococcal granulomas in a horse.

CASE DESCRIPTION: A 7-year-old 509-kg (1,120-lb) Tennessee Walking Horse mare was evaluated because of bilateral mucosanguinous nasal discharge, intermittent right-sided epistaxis, and worsening dyspnea of 9 months' duration. CLINICAL FINDINGS: Multiple masses in the nasopharynx were detected via endoscopic and radiographic examinations. Cytologic and histologic examinations of biopsy specimens of 1 mass revealed round yeasts with thick nonstaining capsules and occasional narrow-based budding that resembled cryptococcal organisms. TREATMENT AND OUTCOME: Oral administration of fluconazole and organic ethylenediamine dihydriodide and intermittent intralesional injections with fluconazole, amphotericin B, and formalin resulted in resolution of lesions for a period of 2.5 years. The horse then developed exophthalmos, recurring clinical signs, and extensive nasopharyngeal masses. The masses were surgically debulked via a large frontonasal bone flap, and the horse was treated with IV injections of amphotericin B and long-term oral administration of fluconazole. Clinical signs did not recur in the following 2-year period. A presumptive diagnosis of cryptococcosis was made following cytologic and histologic evaluations of the masses; results of serologic analysis and fungal culture confirmed infection with Cryptococcus neoformans. CLINICAL RELEVANCE: Cryptococcal infection of the upper respiratory tract in horses has previously been described as a uniformly fatal disease. As this case report illustrates, medical and surgical treatment of sinonasal cryptococcal granulomas in horses may be successful, but the importance of long-term follow-up and the potential for disease recrudescence should be considered. As efficacious antifungal agents become less expensive, their increased use will likely decrease mortality rates in horses with fungal infections.

Canine complete blood counts: a comparison of four in-office instruments with the ADVIA 120 and manual differential counts.

BACKGROUND: With more use of bench-top in-office hematology analyzers, the accuracy of reported values is increasingly important. Instruments use varied methods for cell counting and differentiation, and blood smears may not always be examined. OBJECTIVE: The purpose of this study was to compare canine CBC results using 4 bench-top instruments (Hemavet 950, Heska CBC-Diff, IDEXX LaserCyte, and IDEXX VetAutoread) with ADVIA 120 and manual leukocyte counts. METHODS: EDTA-anticoagulated canine blood samples (n=100) were analyzed on each instrument. Manual differentials were based on 100-cell counts. Linear regression, difference plots, paired t-tests, and estimation of diagnostic equivalence were used to analyze results. RESULTS: Correlations of HCT, WBC, and platelet counts were very good to excellent between all in-office instruments and the ADVIA 120, but results varied in accuracy (comparability). Hemavet 950 and Heska CBC-Diff results compared best with ADVIA results and manual leukocyte differentials. HCT and platelet counts on the IDEXX VetAutoread compared well with those from the ADVIA. Except for neutrophil counts, leukocyte differentials from all instruments compared poorly with ADVIA and manual counts. Reticulocyte counts on the LaserCyte and VetAutoread compared poorly with those from the ADVIA. CONCLUSIONS: The Hemavet 950 and Heska CBC-Diff performed best of the 4 analyzers we compared. HCT, WBC, and platelet counts on the LaserCyte had minimally sufficient comparability for diagnostic use. Except for neutrophils (granulocytes), leukocyte differential counts were unreliable on all in-office analyzers. Instruments with a 5-part leukocyte differential provided no added benefit over a 3-part differential. Assessment of erythrocyte regeneration on the LaserCyte and VetAutoread was unreliable compared with the ADVIA 120.

Comparison of Multistix PRO dipsticks with other biochemical assays for determining urine protein (UP), urine creatinine (UC) and UP:UC ratio in dogs and cats.

BACKGROUND: Urine protein: urine creatinine (UP:UC) ratio determined from the quantitative measurement of protein and creatinine in a single urine sample is the best feasible assessment of clinically significant proteinuria in dogs and cats. A dipstick that measures urine protein, urine creatinine, and UP:UC ratio has been used in human medicine and could have application for veterinary practice. OBJECTIVE: The objective of this study was to compare the Multistix PRO dipstick (Bayer Corporation, Elkhart, IN, USA) to other biochemical methods for determination of urine protein and creatinine, and UP:UC ratio in canine and feline urine. METHODS: A complete urinalysis, including sulfosalicylic acid (SSA) precipitation, was performed on urine samples submitted to our laboratory between February and April 2003 from 100 dogs and 49 cats. Urine protein and creatinine concentrations were determined by the Multistix PRO dipstick using a Clinitek 50 analyzer (Bayer) and compared with the results of SSA precipitation and quantitative biochemical analysis. The UP:UC ratios from the dipstick results (calculated by the Clinitek 50 and also manually) were compared with those calculated from quantitative values. Pearson product-moment correlation analysis and diagnostic sensitivity and specificity (using quantitative results as the gold standard) were determined. RESULTS: For both canine and feline urine, protein and creatinine concentrations determined by the Multistix PRO correlated closely with quantitative concentrations for protein (dogs r = .78, P = .0001; cats r = .87, P = .0001) and creatinine (dogs r = .78, P = .0001; cats r = .76, P = .0001). The Multistix PRO was more sensitive and less specific than SSA precipitation for diagnosing clinically significant proteinuria. UP:UC ratios obtained by manual calculation of dipstick results correlated best with quantitative UP:UC ratios in dogs, and had higher specificity but lower sensitivity for the diagnosis of proteinuria. In cats, UP:UC ratios determined by the dipstick method did not correlate (r = -.24, P = .0974) with quantitative values. CONCLUSIONS: The Multistix PRO, with manual calculation of UP:UC, may be a good alternative for the diagnosis of clinically significant proteinuria in dogs, but not cats. Dipstick creatinine concentration should be considered as an estimate.