Cord serum IgE and early detection of the atopic phenotype: suitable for routine screening?

Cord serum IgE has been shown to be a valuable marker for the prediction of atopy. Our study was designed to verify these findings for possible systematic screening recommendation. Our study consisted of 338 children who were followed from birth to 18 months. Cord serum IgE was measured by paper immunosorbent test and radioimmunoassay. All other data (sex, family history and environment, diet, occurrence of atopic manifestations) were recorded. Of the 338 children, 118 (34.9%) developed obvious clinical symptoms of atopy during the study period. Using the receiver operator curve we found an IgE level of 1.20 IU/ml to be the best cut-off point as a predictor of atopy with 95% specificity but 13% sensitivity. Combination with other predictors such as sex, family history, environmental factors and diet did not increase the predictive value of the test. Because of this low sensitivity we conclude that cord serum IgE is insufficient to detect individuals at risk for atopy even if associated with genetic and environmental factors. Thus it should not be recommended for routine screening purposes; more sensitive markers are needed.