Standardization of Allergenic Extracts
The purpose of allergen standardization is to make proper allergenic material available for use in diagnosis and treatment. The performance of standardization requires the presence of standards. The subcommittee on allergen standardization of the International Union of Immunological Societies (I.U.I.S.) has prepared a number of international standards (IS) available through WHO. The IS were selected allergen specialists on the basis of detailed specifications to ensure typical and representative materials. The usefulness and assessibility of standards were confirmed through the performance of international collaborative studies. Comparison between preparations relative to the IS gave results which within limits were independent of method, time and laboratory. These IS are recommended for use as callibrators (i.e. standards for measurements of relative potency) and are not recommended for use as prototypes (i.e. materials to which an extract is to be matched in all respects). The activity of each standard is defined in arbitrary international units (IU) and one IU of a specific standard preparation is not related to the unit activity of another preparation although it may be similar. The IS preparations may be utilized as callibrators for determination of total allergenic activity and/or as callibrators in determination of individual components of allergenic extracts. A number of methods have been shown to be useful for this purpose, but any method giving relevant information on the potency and quality of allergenic extracts can be used. Current international collaborative studies have shown that standardization relative to an IS is possible. Depending on requirements from various national control authorities and the technical ability of allergen extract manufacturers, in the near future only standardized allergenic extracts should be used — for the benefit of allergic patients.
KeywordsAllergy Clin Immunol Grass Pollen International Unit Major Allergen Bermuda Grass
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