Levels of IgE in serum from normal children and allergic children as measured by an enzyme immunoassay.

Serum IgE levels of 346 nonallergic and 301 allergic children were measured by an enzyme immunoassay. The data are presented as the geometric mean +/- 95% confidence interval for each age from less than 1 to 12 years of age with those 13 to 16 years of age, pooled. The geometric mean for nonallergic patients increases from 0.9 IU/ml at less than 1 year of age to 45.4 IU/ml at 13 to 16 years of age. By use of an IgE value between confidence intervals of allergic and nonallergic subjects, a cutoff value for each age was established to differentiate allergic from nonallergic children. This value increases from 10 IU/ml at less than 1 year to 100 IU/ml at 13 to 16 years of age. The diagnostic sensitivity and specificity of the assay, based on the cutoff values, average 83% and 91%, respectively.