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SCIT: Preparation of allergen extracts for therapeutic use

Harold Nelson, MD
Section Editor
Peter S Creticos, MD
Deputy Editor
Anna M Feldweg, MD


Subcutaneous immunotherapy (SCIT) is administered differently around the world and even within the United States. Over the past few decades, professional allergy societies in the United States have made attempts to reduce variations in practice and identify best approaches. Practice parameters for SCIT have been published, and the approach described in this topic review is consistent with the American guidelines [1].

Terminology — An allergen immunotherapy extract is a solution of one or more allergens that is used for immunotherapy. This topic review will use the term "allergen immunotherapy extract" or "allergen extract," although other terms in use include "allergy serum," "allergen vaccine," "allergen solution," and "allergen product" [1].

The preparation of allergen extracts for use in SCIT, including effective doses, types of extracts, mixing of different allergens, training of compounding personnel, storage and stability, and recording of vaccine "recipes" will be discussed in this topic review. Administration techniques, schedules, and choice of allergens, as well as an overview of the manufacture of allergen extracts are reviewed separately. (See "Subcutaneous aeroallergen immunotherapy: Accelerated schedules (cluster and rush)" and "Allergen extracts: Composition, manufacture, and labeling".)


Several types of allergen stock solutions are available from commercial sources in the United States. The allergen may be in an aqueous solution, a solution containing 50 percent glycerin, in an alum-precipitated form, or lyophilized. The manufacture of allergen extracts is reviewed in detail elsewhere. (See "Allergen extracts: Composition, manufacture, and labeling" and 'Dilutions and diluents' below.)

A specific allergen may only be available in a limited number of forms. As examples:

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Literature review current through: Nov 2017. | This topic last updated: Oct 05, 2017.
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  26. Vendors that supply media-fill tests are listed at the following site: https://www.aaaai.org/Aaaai/media/MediaLibrary/PDF%20Documents/Practice%20Management/Media-fill-test-vendors.pdf (Accessed on May 18, 2017).