a competition test, performed in vitro, used to measure IgE specific for a particular antigen. Known amounts of radiolabeled IgE compete with the patient's unlabeled IgE to bind to a surface coated with anti-IgE. The reduction in radiolabeled IgE due to the presence of IgE in the patient's serum can be determined by comparison with known IgE standards; thus, the amount of the patient's total serum IgE can be determined.
