Evaluation of the scil vCell 5, a novel laser- and impedance-based point-of-care hematology analyzer, for use in dogs and cats

A novel laser- and impedance-based point-of-care hematology analyzer (POCA), the vCell 5 (scil Animal Care), providing a complete blood count with 5-part leukocyte differential count has recently been introduced to veterinary laboratories. We evaluated the analyzer for use in dogs and cats including method comparison and assessment of linearity, carryover, and precision. Fresh blood samples from 192 healthy and diseased dogs and 159 cats were analyzed, and results were compared to reference methods (i.e., microhematocrit [PCV], Advia 2120 hematology analyzer). Total observed error (TEo) was calculated from CV, obtained at 3 concentrations, and bias%, and compared to total allowable error (TEa). For both species, excellent correlation (r_s = 0.93-0.99) was seen between methods for WBC and RBC, hematocrit, hemoglobin, and platelet counts (PLT), except for feline PLT (r_s = 0.79). Quality requirements (TEo < TEa) were fulfilled for WBC (TEo = 8.6-11.1%; TEa = 20%) and RBC (TEo = 3.5-7%; TEa = 10%), hematocrit (TEo = 5.7-9.4%; TEa = 10%), PCV (cat TEo = 7.8%; TEa = 10%), mean corpuscular volume (cat TEo = 5.1%; TEa = 7%), and PLT (TEo = 13.1-24.1%; TEa = 25%). Excellent linearity was demonstrated for WBC, RBC, and PLT, and hemoglobin. CVs of <2% for WBC, RBC, hematocrit, hemoglobin, and of <5% (dog) and 8% (cat) for PLT were demonstrated for values within the RI. Except for calculated variables and well-known species-specific deviations in feline PLT, scil POCA results were correlated favorably with reference method results and complied with quality requirements for cats and dogs.

Analytical performance and method comparison of a quantitative point-of-care immunoassay for measurement of bile acids in cats and dogs

Point-of-care analyzers (POCAs) for quantitative assessment of bile acids (BAs) are scarce in veterinary medicine. We evaluated the Fuji Dri-Chem Immuno AU10V analyzer and v-BA test kit (Fujifilm) for detection of feline and canine total serum BA concentration. Results were compared with a 5th-generation assay as reference method and a 3rd-generation assay, both run on a bench-top analyzer. Analytical performance was assessed at 3 different concentration ranges, and with interferences. For method comparison, samples of 60 healthy and diseased cats and 64 dogs were included. Linearity was demonstrated for a BA concentration up to 130 µmol/L in cats (r = 0.99) and 110 µmol/L in dogs (r = 0.99). The analyzer showed high precision near the lower limit of quantification of 2 µmol/L reported by the manufacturer. Intra- and inter-assay coefficients of variation were < 5% for both species and all concentrations. Interferences were observed for bilirubin (800 mg/L) and lipid (4 g/L). There was excellent correlation with the reference method for feline (rs = 0.98) and canine samples (rs = 0.97), with proportional biases of 6.7% and -1.3%, respectively. However, a large bias (44.1%) was noted when the POCA was compared to the 3rd-generation assay. Total observed error was less than total allowable error at the 3 concentrations. The POCA reliably detected feline and canine BA in clinically relevant concentrations.

Traditional and quantitative analysis of acid-base and electrolyte imbalances in horses competing in cross-country competitions at 2-star to 5-star level

Background

Early recognition and management of acid‐base, fluid, and electrolyte disorders are crucial for the maintenance of health and performance in equine athletes.

Objectives

To analyze changes in acid‐base and electrolyte status associated with exercise during cross‐country competitions at different levels using traditional and quantitative approaches.

Animals

Thirty‐eight eventing horses.

Methods

Prospective observational study. Jugular venous blood samples were collected before and after the cross‐country test of 25 international eventing competitions ranging from 2‐star (formerly 1‐star) to 5‐star (formerly 4‐star) level. Blood gas analysis was performed to determine pH, pCO₂, Na⁺, Cl⁻, and K⁺ and calculate HCO₃⁻, tCO₂ base excess (BE_ECF), anion gap (AG), strong ion difference calculated from Na⁺, K⁺, Cl⁻, and lactate⁻ (SID₄), strong ion difference calculated from Na⁺, K⁺, and Cl⁻ (SID₃), strong ion gap (SIG), and total nonvolatile weak buffer concentration (A_tot). Postexercise acid‐base imbalances, diagnosed on the basis of the traditional approach, and the simplified strong ion model were compared.

Results

Significant decreases in pH, Cl⁻, SID₄, pCO₂, HCO₃⁻, tCO₂, and BE_ECF as well as increases in K⁺, SID₃, AG, TP, and A_tot were observed between pre‐ and postexercise samples. The changes in acid‐base parameters were significantly affected by the competition level. Using the strong ion approach, a higher proportion of horses was diagnosed with postexercise metabolic acidosis.

Conclusions and Clinical Importance

Regarding the complex acid‐base changes in horses competing at cross‐country competitions, the quantitative approach provided a more detailed analysis of the different factors contributing to acid‐base balance than did the traditional approach.

Blood Biochemical Values of Wild Scarlet Macaw ( Ara macao macao) Nestlings and Adults

Blood biochemical values are useful as indicators of disease in veterinary practice and for health assessments of free-ranging animal populations. We analyzed blood biochemical values for free-living nestling and adult scarlet macaws ( Ara macao macao) in southeastern Peru with an Abaxis VetScan VS2 portable analyzer with Avian/Reptilian Profile Plus rotors. The resulting data were used to create provisional age-independent reference intervals for this instrument for wild scarlet macaw nestlings, calculate blood biochemical ranges for this instrument for wild adults, and examine age-related trends in nestlings. Levels of 11 parameters were studied: albumin, aspartate aminotransferase, calcium, creatine kinase, globulin, glucose, phosphorus, potassium, total protein, sodium, and uric acid. Bile acid levels were generally below the instrument detection level and were not evaluated. Most values and their trends with bird age were comparable to those observed in captive large macaw nestlings. Albumin, aspartate aminotransferase, globulin, glucose, total protein, sodium, and uric acid levels increased with nestling age to adulthood. Creatine kinase, phosphorus, and potassium concentrations decreased with age to adulthood. Calcium concentrations did not change between nestlings and adults. These changes in values with age are broadly in agreement with values in other avian species and likely reflect physiologic and developmental changes as nestlings mature.

Impact of Delayed Analysis in Avian Blood Biochemical Values Measured With the Abaxis VetScan VS2

For biochemical analysis with a point-of-care biochemical analyzer, standard procedure is to analyze the sample as rapidly as possible (<1 hour) after venipuncture to minimize any changes in analyte concentrations that might occur over time. However, under some circumstances, such as when collecting blood at remote field sites, a longer delay may be unavoidable. This study evaluates the effect of delayed analysis time under unrefrigerated conditions on avian (psittacine) biochemical analyte concentrations obtained with the VetScan VS2 using Avian/Reptilian Profile Plus rotors. Venipuncture was performed on a group of 36 psittacine birds as part of routine health checks in a research aviary (Texas A&M University, College of Veterinary Medicine, College Station, TX, USA). Whole blood was kept at room temperature and analyzed at 4 time intervals: <1, 3, 6, and 24 hours after venipuncture. At 3 hours or less after collection, most biochemical parameters changed by <2%, with the exception of phosphorus (decrease of about -9%). Major increases by 24 hours after collection were observed in phosphorus (+67%) and potassium (+103%) concentrations, whereas aspartate aminotransferase (AST), uric acid, glucose, and sodium concentrations also showed statistically significant changes. Our results suggest that accurate information from analyses using the VetScan VS2 may be obtained for up to 3 hours after venipuncture without refrigeration, but researchers and clinicians do need to exercise care when interpreting blood chemistry analyte concentrations obtained after multihour delays between venipuncture and sample analysis.