Validation of a Point-of-Care Quantitative Equine IgG Turbidimetric Immunoassay and Comparison of IgG Concentrations Measured with Radial Immunodiffusion and a Point-of-Care IgG ELISA.

Ujvari, S; Schwarzwald, C C; Fouché, Nathalie Elisa; Howard, Judith; Schoster, A (2017). Validation of a Point-of-Care Quantitative Equine IgG Turbidimetric Immunoassay and Comparison of IgG Concentrations Measured with Radial Immunodiffusion and a Point-of-Care IgG ELISA. Journal of veterinary internal medicine, 31(4), pp. 1170-1177. Wiley-Blackwell 10.1111/jvim.14770

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BACKGROUND Point-of-care (POC) diagnostic tests with good sensitivity and specificity are needed for diagnosing failure of transfer of passive immunity (FTPI) in foals. Turbidimetric immunoassays (TIA) have these characteristics and provide quantitative results. A commercially available TIA-based POC test (POC-TIA) has not been validated in horses. OBJECTIVE To validate a POC-TIA and compare results of POC-TIA, a POC-ELISA, and radial immunodiffusion (RID). ANIMALS Heparinized blood samples (n = 127) from 48 hospitalized foals (<12 hour to 48 days). METHODS Prospective validation study. IgG concentrations were measured using RID (gold standard), POC-TIA, and POC-ELISA. Agreement between assays was assessed using Bland-Altman analysis. Sensitivity and specificity were calculated using ROC curves. Inter- and intra-assay coefficients of variation (CVs) and linearity were evaluated for POC-TIA. RESULTS The mean bias (95% limits of agreement) between RID and POC-TIA was -4 (-185 to 176), 27 (-201 to 255), and 308 (-377 to 993) mg/dL for samples with IgG concentrations of <400, 400-800, and >800 mg/dL, respectively. Sensitivity and specificity at optimal cutoff were 94 and 100% for the POC-TIA and 94 and 100% for the POC-ELISA to detect IgG <400 mg/dL, and 85 and 87% (POC-TIA) and 69 and 79% (POC-ELISA) to detect IgG ≤800 mg/dL. Intra- and interassay CVs for POC-TIA ranged between 1.6-3.8 and 11.9-18.8%, respectively. Linearity of the dilution series was preserved (R(2) > 0.96). CONCLUSIONS AND CLINICAL IMPORTANCE The POC-TIA provided unambiguous results and had sufficient sensitivity, specificity, accuracy, and precision to be used as an alternative to other POC tests to assess FTPI in foals.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > Equine Clinic
05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV)
05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > DKV - Central Clinical Laboratory

UniBE Contributor:

Fouché, Nathalie Elisa and Howard, Judith

Subjects:

600 Technology > 630 Agriculture

ISSN:

0891-6640

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Andrea Gassmann-Suter

Date Deposited:

12 Oct 2017 08:37

Last Modified:

12 Oct 2017 08:37

Publisher DOI:

10.1111/jvim.14770

PubMed ID:

28561898

Uncontrolled Keywords:

Failure of transfer of passive immunity Foal Horse Radial immunodiffusion

BORIS DOI:

10.7892/boris.101277

URI:

https://boris.unibe.ch/id/eprint/101277

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