Immunoglobulin G determination for foals in the veterinary practice, which tests are most accurate

Abstract

Monitoring the success of passive transfer of immunoglobulins is important because foals with failure of passive transfer are at increased risk for the development of infection and death during the first month of life. The purpose of this study was to identify which test is most suitable for determining the foal’s IgG concentration in practice. A distinction was made between hospitalized foals and healthy low risk foals in the field. One formula and several screening tests were compared to the IgG concentration measured by turbidimetric immunoassay: total protein, albumin and protein spectrum measured by chemistry analyzers, total protein measured by refractometer and IgG concentration determined by the SNAP Foal IgG Test Kit and glutaraldehyde coagulation test. Blood was collected from 46 foals of seven days of age or younger. The most reliable alternative test for determining the IgG concentration appeared to be the combination of total serum protein measured by a chemistry analyzer and gammaglobulin concentration. A total serum protein of ≥ 49 g/L and a gammaglobulin concentration of ≥ 6 g/L was corresponding with an IgG concentration of ≥ 8 g/L. If the immunoglobulin concentration has to be known in healthy low risk foals in the field, SNAP test can be an alternative test if its weaknesses are recognized.