Comparison of IgG concentrations by radial immunodiffusion, electrophoretic gamma globulin concentrations and total globulins in neonatal foals.
Authors: Tscheschlok L, Venner M, Howard J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Assessing Passive Immunity in Foals—Beyond the Gold Standard Failure of passive transfer (FPT) remains a critical concern in neonatal foal health, with inadequate immunoglobulin concentrations leaving foals vulnerable to sepsis and mortality. Tscheschlok, Venner and Howard (2017) compared three laboratory methods for measuring immunoglobulin status in neonatal foals: radial immunodiffusion (RID, the current reference standard), serum electrophoretic gamma globulin concentration, and total serum globulin quantification. Using a cohort of neonatal foals, the researchers evaluated the correlation and diagnostic agreement between these techniques to establish whether the more accessible electrophoretic and total globulin measurements could reliably substitute for RID testing in routine practice. The findings suggest that serum electrophoretic gamma globulin concentrations provide a valid alternative to RID for identifying FPT, offering practitioners a more readily available screening tool without sacrificing diagnostic accuracy. For equine veterinarians and practice managers seeking to improve foal health screening protocols, this work supports the adoption of electrophoretic gamma globulin analysis where RID facilities are unavailable, whilst total globulin measurements alone appear less reliable for this purpose.
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Practical Takeaways
- •IgG-RID is the most reliable method for diagnosing FTPI in foals; use this when accurate assessment of passive transfer failure is critical for treatment decisions
- •Electrophoretic gamma globulin and total globulin measurements offer potential non-invasive alternatives that may be more practical in field settings if validated against RID standards
- •Semi-quantitative point-of-care tests should be used cautiously and confirmed with quantitative methods when FTPI diagnosis will substantially affect foal management or prognosis
Key Findings
- •Radial immunodiffusion (IgG-RID) remains the diagnostic gold standard for quantifying immunoglobulins in foals with FTPI
- •Serum electrophoretic gamma globulin (EGG) concentrations and total globulin measurements may serve as alternative diagnostic markers for assessing FTPI
- •Semi-quantitative tests are commonly used for routine FTPI diagnosis but their accuracy relative to gold standard methods requires further validation