Usefulness of a commercial equine IgG test and serum protein concentration as indicators of failure of transfer of passive immunity in hospitalized foals.

The research investigates the efficacy of a commercial equine IgG test along with serum protein concentration in indicating failure of transfer of passive immunity (FTPI) in newborn foals. Despite the low specificity observed, the study acknowledges the potential usefulness of the IgG test when used considering the properties of the test and the characteristics of the foal. Moreover, while serum total protein and serum globulin concentrations were found to be poor sole indicators of FTPI, their utility as adjunctive tests was recognized.

Methodology

• The study involved 67 hospitalized foals under 19 days old.
• Our researchers used a commercial equine IgG test (SNAP Foal IgG Test Kit) to diagnose FTPI.
• Furthermore, serum IgG concentration was determined with single radial immunodiffusion and the SNAP test.
• The levels of serum total protein (STP) and serum globulin (SG) were evaluated using a clinical chemistry analyzer.

Results

• The SNAP test was repeated on 37 samples from 29 foals, with identical results in 24 samples. This is represented by a kappa statistic of 0.64 with a 95% confidence interval of 0.46-0.82.
• The SNAP test showed a sensitivity of 90% in detection of serum IgG concentration less than or equal to 400mg/dl and 95% sensitivity when the concentration was less than or equal to 800mg/dl.
• The specificity of the same test, however, was relatively low: 79% and 52% for the respective IgG concentration thresholds.
• The sensitivity for detecting less than or equal to 400mg/dl IgG concentration was not affected by plasma fibrinogen concentration, sepsis score, or bacteremia.
• Specificity to detect below or equal to 800mg/dl IgG concentration was notably lower in foals with sepsis scores below or equal to 11 and bacteremia.
• STP and SG concentrations alone did not provide adequate indication of FTPI.

Conclusion

• The efficacy of the SNAP test in hospitalized foals is compromised due to low specificity but can still be useful provided its properties and the characteristics of the foal are considered in interpreting the results.
• While SG and STP concentrations alone offered little assistance in indicating FTPI, they may offer meaningful information when utilized as supplementary tests.