COMPARISON OF 2 IN-VITRO ASSAYS, RAST AND CAP, WHEN APPLIED TO THE DIAGNOSIS OF ANAPHYLACTIC REACTIONS TO HONEYBEE OR YELLOW JACKET VENOMS - CORRELATION WITH HISTORY AND SKIN-TESTS

We compared the results obtained with a new specific IgE assay (Pharma cia CAP system) to those of RAST and intradermal skin tests (ST) perfo rmed in 87 patients with a history of generalized reaction to honeybee or yellow jacket venom. When CAP and RAST were compared with positive ST performed with honeybee venom, CAP sensitivity was not significant ly higher (98%) than that of RAST (95%). When yellow jacket venom was tested, CAP sensitivity (93%) was clearly superior to that of RAST (40 %). When we compared the specificities of RAST and CAP to bee venom, R A ST was positive in 21% of the 24 subjects with negative ST, and CAP in 42%. Among the 29 patients with negative ST to yellow jacket venom, RAST was positive in 17% and CAP in 28%. These results do not reflect a lower specificity of CAP, because CAP positivities could be inhibit ed in vitro, and because, in three patients with a history of anaphyla ctic reaction (one to honeybee, two to yellow jacket), CAP was the onl y positive test confirming the clinical observation. Among the 53 pati ents who were able to identify the offending insect (honeybee, 31; yel low jacket, 22), the cause of the anaphylactic reaction was usually co nfirmed by ST and CAP: honeybee venom 97% for both ST and CAP; yellow jacket venom 82% for ST, 86% for CAP. This was not the case for RAST, which confirmed honeybee venom hypersensitivity in 87% and yellow jack et venom hypersensitivity in only 41%. Thus, CAP is both more sensitiv e and more rapid than RAST, without losing specificity.