INTERPRETATION OF IgE-MEDIATED ALLERGY TESTS (RAST)

The diagnosis of an allergy in a patient can be very complicated. Over the years a number of methods have been developed for the detection of the small amounts of specific-IgE (sIgE) in human serum. Selecting the appropriate allergy test can be difficult and it should be in context of a patient’s clinical presentation. The relevance of a test may also vary according to the patient’s age, allergen exposure, and performance characteristics of the selected test method. It is important to note that positive sIgE results only indicate sensitisation, and are not diagnostic of the allergy without the appropriate exposure history. Large panels of indiscriminately performed allergy tests may therefore, provide misleading information if not interpreted correctly. Cross-reacting proteins/allergens, that may or may not have clinical relevance to allergic disease, may also influence tests for sIgE. It is thus clear that several factors should be taken into consideration when selecting and interpreting a sIgE allergy test.