Comparison of IgG concentrations by radial immunodiffusion, electrophoretic gamma globulin concentrations and total globulins in neonatal foals

Tscheschlok, Lisa; Venner, Monica; Howard, J. (2017). Comparison of IgG concentrations by radial immunodiffusion, electrophoretic gamma globulin concentrations and total globulins in neonatal foals. Equine veterinary journal, 49(2), pp. 149-154. Wiley-Blackwell 10.1111/evj.12575

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REASONS FOR PERFORMING STUDY: Failure of transfer of passive immunity (FTPI) in foals is associated with a risk of infection and death. The current diagnostic gold standard is quantification of immunoglobulins using radial immunodiffusion (IgG-RID). Routine diagnosis is often performed using semi-quantitative tests. Concentrations of serum electrophoretic gamma globulins (EGG) and total globulins may be useful to assess FTPI, but few studies have investigated their use. OBJECTIVES: To assess agreement between IgG-RID and EGG, and evaluate the accuracy of total globulin concentration to diagnose FTPI based on both IgG-RID and EGG. STUDY DESIGN: Prospective study. METHODS: 360 serum samples were harvested at 6-24 hours post natum from 60 German Warmblood foals. Concentrations of EGG, IgG-RID and total globulin concentration (calculated from total proteins and albumin) were measured. Agreement between EGG and IgG-RID was assessed using Bland-Altman plots and Passing-Bablok regression. The accuracy of total globulin concentration was assessed using rank correlation and ROC curve analysis. RESULTS: Good agreement was found with slightly lower EGG than IgG-RID concentrations (Bland-Altman systemic bias, -1.9 g/L) which was more pronounced at higher concentrations (regression equation: IgG-RID = -0.78 +1.28xEGG). Correlations between total globulin concentration and EGG, and total globulin concentration and IgG-RID were 0.93 and 0.79, respectively. The area under the curve was 0.982 and 0.952 for EGG <4 g/L and <8 g/L, and 0.953 and 0.899 for IgG-RID <4 g/L and <8 g/L. Sensitivities and specificities of total globulin concentration in the diagnosis of FTPI were comparable to commonly used screening tests, but cut-offs could be selected to achieve sensitivities of >95% with 71.2% (IgG-RID) and 90.5% (EGG) specificity for <4 g/L, and >90% with 66.0% (IgG-RID) and 87.9% (EGG) specificity for <8 g/L. CONCLUSIONS: There is good agreement between EGG and IgG-RID, with slightly more conservative estimates of immunoglobulins obtained using EGG. Total globulins may be a useful and economic quantitative screening test with cut-offs achieving high sensitivities, but analyser-specific cut-offs may be necessary. This article is protected by copyright. All rights reserved. KEYWORDS: IgG; electrophoresis; foal; globulins; horse; radial immunodiffusion. This article is protected by copyright. All rights reserved.

Item Type:

Journal Article (Original Article)

Division/Institute:

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

UniBE Contributor:

Howard, Judith

ISSN:

0425-1644

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Judith Howard

Date Deposited:

02 Aug 2016 11:06

Last Modified:

02 May 2018 08:16

Publisher DOI:

10.1111/evj.12575

PubMed ID:

27037614

Uncontrolled Keywords:

IgG; electrophoresis; foal; globulins; horse; radial immunodiffusion

BORIS DOI:

10.7892/boris.84551

URI:

https://boris.unibe.ch/id/eprint/84551

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