Quantitative IgE antibody assays in allergic diseases

During the past several years, immunoassays for specific IgE antibodies hav e been refined to permit reporting results in mass units. Thus quantitative immunoassays for IgE antibodies may be an adjunct to skin tests. In cases of food allergy among children with atopic dermatitis, cutoff values for Ig E antibody concentrations to egg, milk, peanut, and fish have been derived to provide 95% positive and 90% negative predictive values. Food-specific I gE antibody determinations can also be used to predict which food allergies are resolving spontaneously. Elevated egg-specific IgE antibody levels in infancy are associated with significantly increased risk for development of inhalant allergies later in childhood. In cases of inhalant allergy, speci fic IgE antibody levels correlate closely with results of inhalation challe nge studies in cat-sensitive persons. Also, mite-specific IgE antibody leve ls correlate significantly with the mite allergen contents of reservoir dus t in the homes of mite-sensitive persons. Immunoassays for quantitation of specific IgE antibodies may be used to document allergen sensitization over time and to evaluate the risk of reaction on allergen exposure. However, i mmunoassays and skin tests are not entirely interchangeable, and neither wi ll replace the other in appropriate circumstances.