Allergen extracts. Standardization of preparations for bronchial provocation tests. A position paper

Abstract

Standardization of allergen provocation tests of the airways requires standardization of each of the steps involved, including standardization of the extracts used. The value of international standards is emphasized and so is the determination of a clinically relevant potency. The allergen extracts used for bronchial provocation tests must be compared with qualitatively and quantitatively clinically relevant standards using complementary immunochemical and biological methods. Ideally the same extracts should be used for diagnosis (skin test, specific IgE determinations, provocations) and treatment (immunotherapy). The importance of the biological compared with the non-biological methods is that the biological methods are established in allergenic patients in order to select a clinically relevant potency of the allergen in question, and this potency ought to be confirmed in clinical trials. Once established the biological potency of an in-house preparation can be reproduced by supplementary in vitro methods. Very few commercial allergen preparations are available which fulfil the above-mentioned criteria.