Procedure for a Standardized Preparation of Skin Prick Test Solutions for the Diagnosis of Occupational Type I Allergies in the Absence of Commercial Extracts

In order to ensure valid diagnostics for occupational test allergen solutions despite the ongoing reduction in the availability of commercial test extracts, a plan B was initiated for the possible production of skin prick test (SPT) solutions in public pharmacies. For important occupational allergen sources (wheat and rye, storage mites, animal epithelia, mold material) laboratory extraction methods were analyzed in comparison to pharmacy compatible extraction methods regarding protein quantity and quality in SDS-PAGE combined with silver staining. Subsequently, using the example of bovine epithelia, adapted extraction procedures as well as in-process and final product controls were transferred to a public pharmacy. Allergen sources with a high protein content, such as wheat and rye grains as well as storage mites, showed good comparability of the extractable protein quantity and protein pattern, regardless of the applied extraction method. In contrast, allergen source materials with a low total protein content, such as animal epithelia and molds, can benefit from laboratory extraction conditions such as mechanical disruption and specific buffer additives. In the qualitative protein silver staining, characteristic protein patterns were identified for each allergen source. Depending on the extraction method, only minor differences in total protein patterns were observed in animal epithelia and molds. Using source materials from two suppliers, the resulting allergen extracts displayed clear differences in protein content in storage mites and quantitative and qualitative differences in molds. A practical preparation attempt of SPT solutions in a public pharmacy was successful. SPT solutions prepared with adapted pharmacy extraction methods showed a comparable protein and Bos d 2 allergen content and equivalent qualities in the protein pattern compared to a previously available commercial SPT solution. Accordingly, it can be assumed that standardized SPT solutions with sufficient allergen quality for occupational allergen sources can be prepared in public pharmacies if certified allergen sources with appropriate protein content are available.