RESUMO
BACKGROUND: Otolaryngologists commonly use glycerin and normal saline with phenol (NSP) in diluting solutions to help preserve allergenicity in immunotherapy vials. Studies have shown that diluting with human serum albumin (HSA) may provide better allergen stability. The purpose of this study was to assess the ability of various diluents to preserve allergen content in testing/treatment boards (TTBs) and immunotherapy treatment vials (ITVs) at multiple time points. METHODS: TTBs with 4 allergens were prepared with HSA, NSP, 10% glycerin, and 50% glycerin. The major allergen content of the TTBs was measured at creation (time 0), 3 days, 8 weeks, and 18 weeks. Multiallergen ITVs containing the 4 allergens were prepared from the NSP board (diluted to 10% glycerin) and the HSA board (diluted in HSA) at the time of making the freshly prepared TTBs and again 8 weeks later, simulating the creation of ITVs from a "new" and an "old" TTB. The major allergen content of these ITVs was determined at creation and at interval time points thereafter. RESULTS: TTBs and ITVs showed a substantial loss of allergen at day 3. The loss of allergen was more pronounced in the more dilute (#4, #5, and #6) vials. HSA and 50% glycerin showed superior allergen preservation compared to NSP and 10% glycerin in TTBs. HSA showed superior allergen preservation compared to 10% glycerin-NSP in ITVs. CONCLUSION: The use of HSA as a diluent in TTBs and ITVs showed superior allergen preservation compared to NSP and 10% glycerin, particularly for more dilute vials.