Single sIgE for Dermatophagoides pteronyssinus ( Dp ) is a good screening tool for atopic sensitization

Background:  Only a limited number of publications had evaluated the Phadiatop application for aeroallergen screen in allergic respiratory diseases (ARD) in the Chinese population. In our retrospective cohort, through studying the Phadiatop versus total IgE use in aeroallergen workups, and local aeroallergen sensitisation profiles by reviewing aeroallergen sIgE, we aimed to derive a cost-effective algorithm for ARD workup. Methods: We have retrospectively identified 694 patients with ARD in 2010-2019, and reviewed their Phadiatop test performed in our tertiary immunology laboratory. Other associated workups including total IgE, and/or allergen specific sIgE (sIgE), if available, were retrieved and analysed. Besides, a further review was performed on 53 consecutive samples collected during January 2021, for aeroallergen screening. Cost effectiveness of the existing protocol (Phadiatop screening followed by individual aeroallergen characterisation) was compared with a new testing algorithm, which started with dust mite ( Dermatophagoides pteronyssinus , Dp) allergy detection. Results: Phadiatop positivity was 67.3%, while total IgE positivity was 66.7% in the 366 patients with the test done. Overall, the agreement of these two tests was 73.5%. Asthmatic patients can be screened positive with total IgE than Phadiatop (34.9%-45.6%). Dp was the most prevalent aeroallergen (> 90%), and its sIgE level correlated best with the Phadiatop sIgE level (R = 0.99, p < 0.001). Comparing to the existing screening using Phadiatop, initial Dp detection is both sensitive and cost effective for ARD in our locality. Conclusions: Screening by Dp sIgE is as sensitive as Phadiatop in aeroallergen screen but of lower running cost. It should be the approach in our locality.