Discriminatory role of history, skin testing and radio-allergo-sorbent test (RAST) in type I-mediated respiratory disease.
The discriminatory role of history, skin testing with common inhalant allergens and RAST was evaluated in patients suffering from asthma, rhinitis, cough, or various combinations of these disorders. Patients were further subdivided into allergic (type I allergy) or non-allergic based on these criteria. When there was any doubt about the allergic etiology, allergen inhalation provocation was performed. Each diagnostic technique was evaluated by means of studying an index, corresponding to an overall evaluation of the importance of the technique studied. For each of these indexes significant differences were found between allergic and non-allergic patients: RAST index proved to be most discriminatory, followed by the history index, whereas the skin test- index was only slightly different between allergic and non-allergic patients. Comparison of the results of the RAST-index before and after the introduction of anti-IgE with specificity for D 2 reveals that the introduction of this new anti-IgE increases the RAST-index values significantly in allergic patients, but not in non-allergic patients. Although the RAST is most discriminatory, the results of this assay have to be evaluated critically since positive allergen provocation tests are still found in 17.7% of patients with negative RAST results, whereas RAST classes 3 and 4 are accompanied 36.8 and 6.4% of the patients respectively with negative provocation tests.
D001249:Asthma / Q000175:diagnosis* / Q000209:etiology; D003371:Cough / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D006801:Humans; D006967:Hypersensitivity / Q000150:complications*; D007428:Intradermal Tests; D011852:Radioallergosorbent Test; D012220:Rhinitis / Q000175:diagnosis* / Q000209:etiology