a radioimmunoassay test to detect specific IgE antibodies responsible for hypersensitivity: the allergen is bound to insoluble material and the patient's serum is reacted with this conjugate; if the serum contains antibody to the allergen, it will be complexed to the allergen. Radiolabeled anti-human IgE antibody is added where it reacts with the bound IgE. The amount of radioactivity is proportional to the serum IgE.