Allergy diagnosis with the radioallergosorbent test: A comparison with the results of skin and provocation tests in an unselected group of children with asthma and hay fever

Abstract

The radioallergosorbent test (RAST) has been used for in vitro diagnosis of asthma and hay fever in children as an integrated part of the routine procedure for allergy diagnosis. A positive RAST test was combined with a positive prick test in 196 235 (80 per cent) tests and with a positive provocation test in 163 182 (90 per cent) tests. When the provocation test was positive to dry pollen, the stock solution ( 1 10 w./v. or 10,000 PNU) of the allergen extract RAST was quite often negative, a fact that explains the lower degree of correlation for a negative RAST test. A comparison between the prick test and the provocation test revealed a high proportion, 54 146 (37 per cent), of positive prick tests that could not be confirmed by the provocation test. RAST is a simple, reliable test for IgE antibodies that is very useful for in vitro diagnosis of atopic allergy on a routine basis. RAST is harmless and less traumatic than skin testing and therefore suitable for use even on very small children. The information obtained on the patient's hypersensitivity is more relevant than that from regular skin testing, probably comparable to skin test titration with selected allergens but not quite as good as provocation testing of the shock organ involved. Whenever a provocation test cannot be performed for each suspected allergen, an RAST test, possibly completed with a prick test, is recommended.