Comparison of the radioallergosorbent test and a quantitative solid-phase radioimmunoassay for the detection of ragweed-specific immunoglobulin E antibody in patients undergoing immunotherapy

Commercially available radioallergosorbent test (RAST) was compared with a quantitative solid-phase polystyrene tube radioimmunoassay (PTRIA) for the detection of ragweed-specific IgE antibody in sera of patients undergoing ragweed immunotherapy. Both assays showed good replication over a wide range of IgE antibody activity. The RAST was limited in the ability to discriminate between sera with high levels of specific IgE antibody. In addition, RAST gave falsely low values of IgE antibody activity in the presence of high levels of blocking antibody.