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Validation of a commercially available automated canine-specific immunoturbidimetric method for measuring canine C-reactive protein.

Hillström A, Hagman R, Tvedten H, Kjelgaard-Hansen M - Vet Clin Pathol (2014)

Bottom Line: Studies of imprecision, accuracy, prozone effect, interference, limit of quantification, and stability under different storage conditions were performed.The method was linear under dilution, and no prozone effect was detected at a concentration of 1200 mg/L.Healthy dogs had CRP concentrations that were less than the limit of quantification of the Gentian cCRP method (6.8 mg/L).

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.

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Bland–Altman difference plot for C-reactive protein (CRP) concentrations in canine sera measured with a new automated canine-specific immunoturbidimetric CRP method and a human CRP assay previously validated in dogs (Randox) (n = 46). The methods were not identical within inherent imprecision, as 21 observations (46%) were not within the dotted lines representing 0 ± 1.96 × inherent imprecision of both methods (3.2%). Open symbols represent samples that were analyzed undiluted, whereas filled symbols were autodiluted by the instrument. Autodilution was performed for samples > 241 mg/L by the Randox method (dilution 1:3), and for samples > 300 mg/L by the Gentian method (dilution 1:5), and the difference between the methods was most pronounced for samples that were autodiluted.
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fig04: Bland–Altman difference plot for C-reactive protein (CRP) concentrations in canine sera measured with a new automated canine-specific immunoturbidimetric CRP method and a human CRP assay previously validated in dogs (Randox) (n = 46). The methods were not identical within inherent imprecision, as 21 observations (46%) were not within the dotted lines representing 0 ± 1.96 × inherent imprecision of both methods (3.2%). Open symbols represent samples that were analyzed undiluted, whereas filled symbols were autodiluted by the instrument. Autodilution was performed for samples > 241 mg/L by the Randox method (dilution 1:3), and for samples > 300 mg/L by the Gentian method (dilution 1:5), and the difference between the methods was most pronounced for samples that were autodiluted.

Mentions: The method comparison study was performed over a period of 23 days. Thirty-eight fresh and 11 frozen samples, in total 49 specimens, were included. Three samples had CRP concentrations below LoQ for the Gentian method (6.8 mg/L), and with the Randox method, these samples had CRP concentrations < 10 mg/L. For the remaining 46 samples, the Passing– Bablok regression analysis revealed small constant and proportional errors with intercept 7.3 mg/L (95% CI 5.1–11.7 mg/L) and slope 0.92 (95% CI 0.88–0.95) (Figure 3). The correlation coefficient (r) was.995. For samples that were not diluted for any of the methods (n = 33), there was no constant or proportional error; the intercept was 2.2 mg/L (95% CI −1.2–5.8 mg/L), and the slope was 0.98 (95% CI 0.95–1.01). Thirteen samples with high CRP concentrations were autodiluted with either the Randox or both methods. Due to the low number of diluted samples, no regression analysis was performed for this subgroup of samples, but there appeared to be mainly a constant error, with Randox measuring approximately 11% higher values than the Gentian method. The Randox and Gentian methods were not identical within the inherent imprecision of both methods, because > 5% of the observations were outside the limits representing the 0 ± 95% CI of the combined inherent imprecision (Figure 4).


Validation of a commercially available automated canine-specific immunoturbidimetric method for measuring canine C-reactive protein.

Hillström A, Hagman R, Tvedten H, Kjelgaard-Hansen M - Vet Clin Pathol (2014)

Bland–Altman difference plot for C-reactive protein (CRP) concentrations in canine sera measured with a new automated canine-specific immunoturbidimetric CRP method and a human CRP assay previously validated in dogs (Randox) (n = 46). The methods were not identical within inherent imprecision, as 21 observations (46%) were not within the dotted lines representing 0 ± 1.96 × inherent imprecision of both methods (3.2%). Open symbols represent samples that were analyzed undiluted, whereas filled symbols were autodiluted by the instrument. Autodilution was performed for samples > 241 mg/L by the Randox method (dilution 1:3), and for samples > 300 mg/L by the Gentian method (dilution 1:5), and the difference between the methods was most pronounced for samples that were autodiluted.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257579&req=5

fig04: Bland–Altman difference plot for C-reactive protein (CRP) concentrations in canine sera measured with a new automated canine-specific immunoturbidimetric CRP method and a human CRP assay previously validated in dogs (Randox) (n = 46). The methods were not identical within inherent imprecision, as 21 observations (46%) were not within the dotted lines representing 0 ± 1.96 × inherent imprecision of both methods (3.2%). Open symbols represent samples that were analyzed undiluted, whereas filled symbols were autodiluted by the instrument. Autodilution was performed for samples > 241 mg/L by the Randox method (dilution 1:3), and for samples > 300 mg/L by the Gentian method (dilution 1:5), and the difference between the methods was most pronounced for samples that were autodiluted.
Mentions: The method comparison study was performed over a period of 23 days. Thirty-eight fresh and 11 frozen samples, in total 49 specimens, were included. Three samples had CRP concentrations below LoQ for the Gentian method (6.8 mg/L), and with the Randox method, these samples had CRP concentrations < 10 mg/L. For the remaining 46 samples, the Passing– Bablok regression analysis revealed small constant and proportional errors with intercept 7.3 mg/L (95% CI 5.1–11.7 mg/L) and slope 0.92 (95% CI 0.88–0.95) (Figure 3). The correlation coefficient (r) was.995. For samples that were not diluted for any of the methods (n = 33), there was no constant or proportional error; the intercept was 2.2 mg/L (95% CI −1.2–5.8 mg/L), and the slope was 0.98 (95% CI 0.95–1.01). Thirteen samples with high CRP concentrations were autodiluted with either the Randox or both methods. Due to the low number of diluted samples, no regression analysis was performed for this subgroup of samples, but there appeared to be mainly a constant error, with Randox measuring approximately 11% higher values than the Gentian method. The Randox and Gentian methods were not identical within the inherent imprecision of both methods, because > 5% of the observations were outside the limits representing the 0 ± 95% CI of the combined inherent imprecision (Figure 4).

Bottom Line: Studies of imprecision, accuracy, prozone effect, interference, limit of quantification, and stability under different storage conditions were performed.The method was linear under dilution, and no prozone effect was detected at a concentration of 1200 mg/L.Healthy dogs had CRP concentrations that were less than the limit of quantification of the Gentian cCRP method (6.8 mg/L).

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.

Show MeSH
Related in: MedlinePlus