RT Journal Article T1 Basophil activation test positivity decreases with time in immediate allergic reactions to proton pump inhibitors A1 Fernández-Santamaría, Rubén A1 Salas, Maria A1 Ariza Veguillas, Adriana A1 Jiménez, María A. A1 González-Mendiola, María R. A1 Sánchez, María L. A1 Boteanu, Cosmin A1 Mayorga Mayorga, Cristobalina A1 Fernández-Duarte, Tahía Diana A1 Torres, María José A1 Laguna, José J. K1 Anafilaxia AB Omeprazole is a widely prescribed proton pump inhibitor [1], with 1%–3% of adverse reactions being reported. Up to 86% of these reactions are IgE mediated [2] and half of them anaphylaxis [1]. An accurate diagnosis is essential, with skin testing (STs) showing high specificity and positive predictive value (PPV) (100%), but lower sensitivity (60%) and negative predictive value (NPV) (70%–90%) [2]. As stated in a recent position paper of the European Academy of Allergy and Clinical Immunology (EAACI), the basophil activation test (BAT) is a reliable option in the diagnosis of immediate hypersensitivity to proton pump inhibitors [3]. In fact, previous research from our group reported that BAT has a higher sensitivity than STs (73.8%) and similar specificity, PPV (100%) and NPV (66.7%) [1]. Interestingly, the combination of STs and BAT can increase sensitivity up to 85.7%, being BAT positive in 57.1% of patients with negative STs [1]. PB Wiley YR 2024 FD 2024-11-27 LK https://hdl.handle.net/10630/36583 UL https://hdl.handle.net/10630/36583 LA eng NO Fernandez-Santamaria, R., Salas, M., Ariza, A., Jiménez, M.A., González-Mendiola, M.R., Sanchez, M.L., Boteanu, C., Mayorga, C., Fernandez, T.D., Torres, M.J. and Laguna, J.J. (2025), Basophil Activation Test Positivity Decreases With Time in Immediate Allergic Reactions to Proton Pump Inhibitors. Allergy. https://doi.org/10.1111/all.16406 NO Funding for open access charge: Universidad de Málaga/CBUAThis work was supported by Institute of Health ‘Carlos III’ (ISCIII) of the Ministry of Economy and Competitiveness (MINECO), grants co-funded by European Regional Development Fund: PI15/01206, PI17/01237, PI18/00095, PI20/01734, PI21/0329, PI21/00969, RETICS ARADYAL RD16/0006/0001, RD16/0006/0033, RICORS Red de Enfermedades Inflamatorias (REI) RD21/0002/0008; Andalusian Regional Ministry of Health: grants PI-0241-2016, PE-0172-2018, PI-0127-2020; Grants from SEAIC, Luis Alvarez 2022 IDIPAZ Fundation and the XV Call for Research Project Development Grants from the Alfonso X el Sabio University Foundation. Funding for open access charge: Universidad de Málaga/CBUA. CM (RC-0004-2021) and AA (C1-0007-2023) holds a ‘Nicolas Monardes’ research contract from the Andalusian Regional Ministry of Health. DS RIUMA. Repositorio Institucional de la Universidad de Málaga RD 21 ene 2026