RAST and skin test screening in the investigation of asthma.

We studied 72 adult asthmatics prospectively for the purpose of detecting atopy by the use of screening methods employing total serum IgE, RAST and prick tests. Fifty-one of the patients were considered to be atopic on the basis of prick test reactivity or a positive RAST. Although the total IgE values of the atopic and nonatopic individuals demonstrated some overlap, values over 150 U/mL were found only in atopics. We determined that 89% of the atopic individuals could be detected by a combination of total IgE greater than 150 U/mL and the use of five specific IgE determinations from the frequency of positive RAST to 20 environmental antigens. Ninety percent of the atopics were detected by four prick tests. Regional data are required to develop and effective set of screening tests. The use of such tests can reduce costs and technical time in the investigation of atopy.