Evaluation of a test kit for determination of serum immunoglobulin G concentration in foals

The accuracy of an immunoglobulin (Ig) G test kit for the semiquantitative measurement of IgG concentration was evaluated with serum from 88 foals. Failure of passive transfer (IgG less than 400 mg/dl) was correctly identified in each of 34 samples, and partial failure of passive transfer (400 less than or equal to IgG less than 800 mg/dl) was correctly identified in each of nine samples. Evidence of adequate passive transfer (IgG greater than or equal to 800 mg/dl) was detected in 44 of 45 samples. One sample with 800 mg/dl or more of IgG was incorrectly classified as a partial failure of passive transfer (Kendall Tau - b = .975). The high degree of accuracy, especially without any errors of overestimation of IgG concentrations, indicated that the IgG test kit should be a useful assay for rapidly determining the passive transfer status of foals.