In vitro testing for immunoglobulin E-mediated food allergies.
The role of immunoglobulin E-mediated food allergy in subjects with allergic disorders, especially in patients with rhinitis and sinusitis, is underestimated by clinicians because of the initial attribution of these disorders to immediate-type hypersensitivity reactions. The difficulties of diagnosing food-related reactions have caused further delay in their recognition and incorporation into the daily practice of diagnosing food allergy. Two of the diagnostic methods for food allergy are the in vitro assay of total immunoglobulin E and the measurement of food-specific immunoglobulin E levels in serum with the radioallergosorbent test. Measurement of specific immunoglobulin E level is the most commonly used but also one of the most controversial techniques. We examined 123 patients with rhinitis who were referred to our otolaryngology/allergy clinic between January and April 1995. All patients received an initial radioallergosorbent test screen, which included milk. We determined the positive predictive value of this positive screen and, in particular, of a positive test for milk in the diagnosis of immunoglobulin E-mediated food allergies in these patients. Conclusions were based on comparison with the result of an additional radioallergosorbent test food panel consisting of eight common and two investigational food allergens.