PT - JOURNAL ARTICLE AU - Jos M. Rooijackers AU - Vanessa Zaat AU - Marcel Veltkamp AU - Martin Meijer AU - Jos Houbraken AU - Emeline Scherer AU - Gabriel Reboux AU - Jan Grutters TI - Home environment exposure assessment in hypersensitivity pneumonitis AID - 10.1183/13993003.congress-2020.795 DP - 2020 Sep 07 TA - European Respiratory Journal PG - 795 VI - 56 IP - suppl 64 4099 - http://erj.ersjournals.com/content/56/suppl_64/795.short 4100 - http://erj.ersjournals.com/content/56/suppl_64/795.full SO - Eur Respir J2020 Sep 07; 56 AB - Objective: To identify the causal agent in hypersensitivity pneumonitis.Method: Between 2015 and 2020 an occupational hygienist performed an exposure assessment in the home environment of patients with hypersensitivity pneumonitis (HP), in whom common causes of HP were excluded. If indicated, work place exposure was assessed. Indoor and outdoor air samples were analysed for fungi. In the case of qualitative or quantitative abnormal patterns in the analysed samples indicating the presence of an etiologic agent, serology (double diffusion/Ouchterlony and electrosyneresis on cellulose acetate) was performed for general panels and specific fungi.Results: Assessment was performed in 41 patients (23-73 yrs). In 8 (20%) a source and causal agent was identified in the home environment, in two cases results were controversial. Main sources were carpets, mouldy bathrooms, poorly maintained dwellings and a car air conditioning. Among causal agents were Aspergillus spp., Penicillium sp., Wallemia sebi, Botrytis cinerea, Trichoderma pseudokoningii, Cephalotrichum sp., Thermoactinomyces vulgaris and goose feathers. Additional exposure assessment in the work place was performed in 8 patients, which revealed a causal agent in another 3 cases and one controversial finding. Sampling repeated in 2 cases after removal of the source showed that the causal agent was no longer present.Conclusion: A causal agent was identified in at least 25% of patients with HP. Standard protocols for indoor air sampling and individual tailored serology may contribute to the diagnosis of HP and intervention (Reboux G, et al. Indoor Air 2019; 29:5-16).This study is part of ZonMw project Topzorg, PRJ140088FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 795.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).