Comparison of IgE values as determined by different solid phase radioimmunoassay methods

Abstract

Accurate measurement of low Ig[immunoglobulin]E concentrations is technically difficult. Results obtained by a direct sandwich [DS] and 3 inhibition methods of radioimmunoassays are compared. For values > 50 U/ml, good correlation was obtained with all methods. Below 50 U/ml, the inhibition methods tended to yield falsely high values. For very low concentrations (1-10 U/ml), the best correlation was obtained between the DS test and the inhibition test using a correction factor to allow for the non-specific effect of serum. The 4 methods were used to quantify IgE in cord serum samples from healthy individuals. The mean value obtained by the DS test was 0.4 U/ml and by the inhibition test, using a correction factor, 0.6 U/ml, respectively. Because of its greater simplicity the DS test is recommended.