Series onTesting and Assessment OECD Series on Testing and Assessment Detailed Review Paper on RespiratorySensitisation This work was approved and declassified by the Chemicals and Biotechnology Committee on 30/07/2026. Please cite this publication as: OECD (2026),Detailed review paper on respiratory sensitisation, OECD Series on Testing and Assessment, OECD Publishing,Paris,https://doi.org/10.1787/b5258246-en. Photo credits: Egorov Artem/Shutterstock.com © OECD 2026 Attribution 4.0 International (CC BY 4.0) This work is made available under the Creative Commons Attribution 4.0 International licence. By using this work, you accept to be bound by the terms of this licence (https://creativecommons.org/licenses/by/4.0/). Attribution–you must cite the work. Translations–you must cite the original work, identify changes to the original and add the following text:In the event of any discrepancy between the original work and thetranslation, only the text of original work should be considered valid. Adaptations–you must cite the original work and add the following text:This is an adaptation of an original work by the OECD. The opinions expressed and arguments employedin this adaptation should not be reported as representing the official views of the OECD or of its Member countries. Third-party material–the licence does not apply to third-party material in the work. If using such material, you are responsible for obtaining permission from the third party andfor any claims of infringement. About the OECD TheOrganisation for Economic Co-operation and Development(OECD)is an intergovernmentalorganisation in which representatives of 38 countries in North and South America, Europe and the Asiaand Pacific region, as well as the European Union, meet to co-ordinate and harmonise policies, discussissues of mutual concern, and work together to respond to international problems. Most of the OECD’swork is carried out by more than 200 specialised committees and working groups composed of membercountrydelegates.Observers from several Partner countries and from interested internationalorganisations attend many of the OECD’s workshops and other meetings. Committees and working groupsare served by the OECD Secretariat, located in Paris, France, which is organised into directorates anddivisions. The Environment, Health and Safety Division publishes free-of-charge documents in twelve differentseries:Testing and Assessment;Good Laboratory Practice and Compliance Monitoring;Pesticides;Biocides;Risk Management;Harmonisation of Regulatory Oversight in Biotechnology;Safety ofNovel Foods and Feeds; Chemical Accidents; Pollutant Release and Transfer Registers; EmissionScenario Documents; Safety of Manufactured Nanomaterials;andAdverse Outcome Pathways.More information about the Environment, Health and Safety Programme and EHS publications is availableon the OECD’s World Wide Web site (https://www.oecd.org/en/topics/chemical-safety-and-biosafety.html). This publication was developed in the IOMC context. The contents do not necessarilyreflect the views or stated policies of individual IOMC Participating Organizations. The Inter-Organisation Programme for the Sound Management of Chemicals (IOMC)was established in 1995 following recommendations made by the 1992 UN Conferenceon Environment and Development to strengthen co-operation and increase internationalco-ordination in the field of chemical safety. The Participating Organisations are FAO,ILO,UNDP,UNEP,UNIDO,UNITAR,WHO,World Bank,Basel,Rotterdam andStockholm Conventions and OECD. The purpose of the IOMC is to promote co-ordinationof the policies and activities pursued by the Participating Organisations, jointly orseparately, to achieve the sound management of chemicals in relation to human healthand the environment. Foreword The project to develop a Detailed Review Paper (DRP) on respiratory sensitisation was initiated byNetherlands, Austria, United States, Luxembourg and ICAPO, in order to facilitate the development of non-animal test methods to predict the respiratory sensitisation potential of low molecular weight chemicals. Given the absence of standardised in vitro methods in this particular area of chemical safety testing, theDRP provides an overview of the state-of-the-science, techniques, and methods available. The DRP wasprepared by an international team of subject matter experts. A dedicated OECD Expert Group was formedto provide input into the draft DRP and two commenting rounds of the Working Party of the NationalCoordinators of the Test Guidelines Programme (WNT) were organised in July and December 2025 tosubject the document to broad review and comments from the regulatory science community. The WNTapproved this Detailed Review Paper at its 38th meeting in April 2026. This document includes twoannexes, provided as separate Excel files. Table of contents About the OECD3 ForewordList of abbreviationsDefinitionsExecutive summary 4 7 11 12 1 Introduction