Radioallergosorbent test (RAST)—reliable tool or poor substitute?1
An in vitro method, the radioallergosorbent test (RAST) has been developed for the detection of allergen-specific antibodies of the IgE class. Review of the literature shows that in comparison to skin testing, the RAST has a high degree of correlation (60% to 90% depending on the antigen); however, this method is not as sensitive as other tests (50% false-negative). The RAST is affected by blocking antibodies (IgG), resulting in false-negative values and high levels of IgE that bind on the allergen discs, giving false-positive findings. Because of these problems, RAST is somewhat limited for use in the clinical setting.