Background and Aims Common variable immunodeficiency (CVID) can affect quality of life (QoL) which can be better assessed with validated scales. Our goal was to validate the Turkish version of the Italian CVID-QoL questionnaire. Methods International recommendations for cultural adaptation and translation process of original scale was followed. CVID patients completed Turkish CVID-QoL questionnaire between October 2019 and January 2020. The Short Form Health Survey (SF-36) was used as a comparative questionnaire. Reliability, reproducibility, factor analysis, content validity, convergent validity and discriminant validity were analysed. Results 50 CVID patients were included in the study. 64 % of patients (n=32), the mean age of the patients was 36.68 ± 13.2 years, the median duration of disease was 52.5 months. The instrument had good internal consistency in 50 patients [Cronbach’s alpha: 0.92, emotional functioning (EF): 0.91, relational functioning (RF): 0.77]. It also revealed high reproducibility in 26 patients QoL global, intraclass correlation coefficient (ICC)= 0.80 (95 % CI 0.56 - 0.91); EF, ICC = 0.78 (95 % CI 0.51- 0.90); RF, ICC = 0.82 (95 % CI 0.59-0.92); Gastrointestinal and skin symptoms (GSS), ICC = 0.89 (95 % CI 0.76-0.95); (p <0.001, p <0.001, p <0.001, p <0.001). QoL global, EF and RF scores showed good convergent validity with similar subscales of SF-36. The number of infections within last 3 months had a significant impact on QoL global, EF and RF (p=0.038, p=0.045, p=0.028). Conclusions The Turkish version of CVID QoL scale has appropriate validity and reliability among Turkish patients with CVID.

Medical Algorithm: Diagnosis and Managemen of Humoral ImmunodeficienciesAnna Šedivá1, Tomáš Milota1, Jiří Litzman2, Isabella Quinti3, ESID Clinical Working Party, EAACI Primary Immunodeficiency Working Group, Stephen Jolles4Department of Immunology, 2nd Faculty of Medicine Charles University, V Uvalu, University Hospital in Motol, Prague, Czech RepublicFaculty of Medicine, Masaryk University Brno, Czech Republic; Department of Clinical Immunology and Allergology, St Anne´s University Hospital, Brno, Czech RepublicDepartment of Molecular Medicine, Sapienza University of Rome, Rome, ItalyImmunodeficiency Centre for Wales, University Hospital of Wales, Cardiff, UKFor ESID Clinical Working Party:Isabelle Meyts, Department of Pediatrics, Leuven University Hospitals, Leuven, BelgiumSiobhan Burns, Institute of Immunity and Transplantation, University College London, London, United Kingdom; Department of Immunology, Royal Free London NHS Foundation Trust, London, United KingdomAuthor´s contributions:AS prepared the concept and wrote the manuscript, TM edited Figures and wrote the manuscript, JL designed Figures and revised manuscript, IQ designed Figures and revised the manuscript, IM revised manuscript, SB revised manuscript, ST edited Figures and wrote the manuscript.