Analytical validation of a point-of-care test and an automated immunoturbidimetric assay for the measurement of canine C-reactive protein in serum.

C-reactive protein (CRP) is an acute phase protein, which is used to evaluate and monitor the response of the innate immune system to a variety of inflammatory processes in the dog. The purpose of this study was to analytically validate a point-of-care assay (IDEXX Catalyst CRP Test) and an immunoturbidimetric assay (Gentian Canine CRP Immunoassay) for the measurement of serum CRP concentrations in dogs. These 2 assays (Catalyst, Gentian) were compared to a previously validated enzyme-linked immunosorbent assay (Tridelta Development EIA Canine CRP Assay). Linearity, precision, reproducibility, and accuracy were assessed using leftover serum samples. Agreement between assays was assessed using leftover serum samples and serum from clinically healthy dogs. Observed to expected ratios (O/E) for dilutional parallelism were 83.9 to 163.1% and 108.3 to 160.6% for the Catalyst and the Gentian assays, respectively. Coefficients of variation for intra-assay variability ranged from 6.4 to 9.5% for the Catalyst assay and 1.5 to 2.6% for the Gentian assay. Coefficients of variation for inter-assay variability ranged from 3.8 to 18.2% for the Catalyst assay and 4.5 to 5.8% for the Gentian assay. The mean O/E for recovery were 97.9% and 98.5% for the Catalyst and Gentian assays, respectively. Correlations between assays were as follows: Catalyst and Tridelta (R 2 = 0.76), Gentian and Tridelta (R 2 = 0.79), and Catalyst and Gentian (R 2 = 0.98). The Catalyst and Gentian assays are both acceptable for measuring CRP in dog serum, but their results are not directly comparable with the Tridelta assay.

La protéine C réactive (CRP) est une protéine de phase aiguë, qui est utilisée pour évaluer et surveiller la réponse du système immunitaire inné à une variété de processus inflammatoires chez le chien. Le but de cette étude était de valider analytiquement un test au point de service (test IDEXX Catalyst CRP) et un test immunoturbidimétrique (Gentian Canine CRP Immunoassay) pour la mesure des concentrations sériques de CRP chez le chien. Ces deux tests (Catalyst, Gentian) ont été comparés à un test immuno-enzymatique précédemment validé (Tridelta Development EIA Canine CRP Assay). La linéarité, la précision, la reproductibilité et l'exactitude ont été évaluées à l'aide d'échantillons de sérum restants. La concordance entre les tests a été évaluée à l'aide d'échantillons de sérum restants et de sérum provenant de chiens cliniquement sains. Les rapports observés/attendus (O/E) pour le parallélisme de dilution étaient de 83,9 à 163,1 % et de 108,3 à 160,6 % pour les tests Catalyst et Gentian, respectivement. Les coefficients de variation pour la variabilité intra-test variaient de 6,4 à 9,5 % pour le test Catalyst et de 1,5 à 2,6 % pour le test Gentian. Les coefficients de variation pour la variabilité inter-test variaient de 3,8 à 18,2 % pour le test Catalyst et de 4,5 à 5,8 % pour le test Gentian. L'O/E moyen pour la récupération était de 97,9 % et de 98,5 % pour les tests Catalyst et Gentian, respectivement. Les corrélations entre les tests étaient les suivantes : Catalyst et Tridelta (R 2 = 0,76), Gentian et Tridelta (R 2 = 0,79) et Catalyst et Gentian (R 2 = 0,98). Les tests Catalyst et Gentian sont tous deux acceptables pour mesurer la CRP dans le sérum de chien, mais leurs résultats ne sont pas directement comparables avec le test Tridelta.(Traduit par Docteur Serge Messier).

Partial analytical validation of the VetScan cPL rapid test.

BACKGROUND: Serum canine pancreatic lipase immunoreactivity (cPLI) concentrations have become the standard laboratory test used to diagnose canine pancreatitis. Recently, a new point-of-care assay for cPLI, the VetScan cPL rapid test (VetScan cPL), has become available, but analytical validation data have not yet been published. OBJECTIVE: This study aimed to perform a partial analytical validation of the VetScan cPL. METHODS: Leftover serum samples from a diagnostic laboratory were used. Adherence to the manufacturer's guidelines, linearity, repeatability, and reproducibility were evaluated. Results of the VetScan cPL were correlated with the Spec cPL results. RESULTS: Observed-to-expected ratios for dilutional parallelism ranged from 77.4% to 162.9% (mean 119.3%). Intra-assay and inter-assay variabilities ranged from 16.9% to 36.7% (mean 25.1%) and from 14.1% to 51.2% (mean 31.8%), respectively. Adherence to the manufacturer's specification regarding results within ± 60 µg/L of the Spec cPL result was only achieved for 39% of the measurements. The VetScan cPL and Spec cPL correlation showed a Spearman's r of .758 for 29 data pairs. CONCLUSIONS: Under the conditions of this study, the VetScan cPL did not adhere to the manufacturer's specifications for most measurements. Also, the VetScan cPL showed suboptimal linearity and was not precise. In conclusion, the VetScan cPL failed basic analytical validation.

Effects of feed-supplementation and hide-spray application of two sources of tannins on enteric and hide bacteria of feedlot cattle.

Pathogenic bacteria attached to the hide or shed in the feces of cattle at slaughter can contaminate carcasses intended to be processed for human consumption. Therefore, new pre-harvest interventions are needed to prevent the carriage and excretion of foodborne pathogens in cattle presented to the processing plant. The objectives of this study were to examine the antimicrobial effects of hydrolysable tannin-rich chestnut and condensed tannin-rich mimosa extracts on bacterial indicators of foodborne pathogens when applied as a hide-intervention and as a feed additive to feedlot cattle. Water (control) or solutions (3 % wt/vol) of chestnut- and mimosa-extract treatments were sprayed (25 mL) at the left costal side of each animal to a 1000 cm² area, divided in four equal quadrants. Hide-swabs samples obtained at pre-, 2-min, 8-h, and 24-h post-spray application were cultured to enumerate Escherichia coli/total coliforms and total aerobic plate counts. In a second experiment, diets supplemented without (controls) or with (1.5 % of diet dry matter) chestnut- or mimosa-extracts were fed during a 42-day experimental feeding period. Weekly fecal samples starting on day 0, and rumen fluid obtained on days 0, 7, 21 or 42 were cultured to enumerate E.coli/total coliforms and Campylobacter. Tannin spray application showed no effect of treatment or post-application-time (P > 0.05) on measured bacterial populations, averaging 1.7/1.8, 1.5/1.6 and 1.5/1.7 (log10CFU/cm²) for E. coli/total coliforms, and 4.0, 3.4 and 4.2 (log10CFU/cm²) in total aerobes for control, chestnut and mimosa treatments, respectively. Mean (± SEM) ruminal E. coli and total coliform concentrations (log(10) CFU/mL) were reduced (P < 0.01) in steers fed chestnut-tannins (3.6 and 3.8 ± 0.1) in comparison with the controls (4.1 and 4.2 ± 0.1). Fecal E. coli concentrations were affected by treatment (P< 0.01), showing the highest values (log10 CFU/g) in fecal contents from mimosa-fed steers compared to controls (5.9 versus 5.6 ± 0.1 SEM, respectively). Total coliforms (log CFU/g) showed the highest values (P < 0.01) in feces from chestnut- and mimosa-fed steers (6.0 and 6.1 ± 0.1 respectively) in comparison with controls (5.7 ± 0.1). Fecal Campylobacter concentrations (log10CFU/g) were affected by treatment (P < 0.05), day (P < 0.001) and their interaction (P < 0.01) with the controls having lower concentrations than chestnut- and mimosa-fed steers (0.4, 1.0, and 0.8 ± 0.3, respectively). It was concluded that under our research conditions, tannins were not effective in decreasing measured bacterial populations on beef cattle hides. Additionally, chestnut tannin reduced E. coli and total coliforms within the rumen but the antimicrobial effect was not maintained in the lower gastrointestinal tract. Further research is necessary to elucidate the possible antimicrobial effects of tannins at site-specific locations of the gastrointestinal tract in beef cattle fed high-grain and high-forage diets.