A quantitative immunofluorescence method for the determination of IgE antibodies in comparison with the radioallergosorbent test (RAST)

A quantitative immunofluorescence technique, the defined antigen substrate spheres (DASS) system, was tested for its suitability for IgE antibody detection. The method is based on the binding of IgE antibodies to a Sepharose-coupled allergen and subsequent quantitation of the bound IgE by a fluorescent anti-IgE antibody. The sensitivity of the method was compared with that of the radioallergosorbent test (RAST), an equivalent radioactive technique. Although the DASS technique was found to be about 10 times less sensitive than the RAST, its sensitivity warrants clinical use, provided highly purified allergen extracts are applied. The method is also suitable for quantitation of the total IgE content in sera with a lower limit of detection of 10 IU/ml serum.