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FeNO Guidelines

The most recognised national and international scientific societies have produced recommendations for FeNO testing to help with more accurate diagnoses and better asthma management:

2022: European Respiratory Society1

  • For diagnosis: FeNO recommended in the diagnosis of asthma in adults if there is uncertainty after spirometry and bronchodilator reversibility testing.

2021: Global Initiative for Asthma2

  • For management: FeNO recommended to assess the severe asthma phenotype during high-dose ICS treatment. FeNO recognised as a predictor of a good response to certain biologic agents.

2021: American Thoracic Society3

  • For management: FeNO testing strongly recommended in addition to usual care to help treat asthma patients.

2021: European Respiratory Society4

  • For diagnosis: FeNO strongly recommended as a first-line test in the diagnosis of asthma in children.

2020: European Respiratory Society and American Thoracic Society5

  • For management: FeNO recommended for the identification of appropriate patients for some biologics.

2020: National Heart, Lung, and Blood Institute (USA)6

  • For diagnosis: Recommends the addition of FeNO measurement for both children (from 5yo*) and adults if the diagnosis of asthma is uncertain after initial assessment or if spirometry cannot be performed.
  • For management: Recommends the addition of FeNO testing for asthma management for both children (from 5yo) and adults if there is uncertainty on choosing and managing ICS after assessment using traditional methods.

2020: Mexican College of Clinical Immunology and Allergy7

  • For diagnosis: Recognises the use of FeNO to assist in diagnosing asthma in both adults and children.
  • For management: In severe asthma, FeNO recommended for endotyping and for detecting poor adherence, undertreatment and risk of exacerbations. FeNO recommended to select the right biological therapy in adults (in children, FeNO use suggested in specific cases). FeNO suggested to titrate ICS and to identify patients at risk of loss of lung function.

2018: Korean Chronic Cough Guideline8

  • For diagnosis: FeNO recommended for the diagnosis of asthma in children and adults.

2017: Canadian Thoracic Society9

  • For severe asthma: FeNO recommended to characterise the severe asthma phenotype.

2017: National Institute for Health and Care Excellence (UK)10

  • For diagnosis: Offer a FeNO test to all adults if a diagnosis of asthma is suspected. Consider a FeNO test in children (5-17yo) if there is diagnostic uncertainty after initial assessment.
  • For management: Consider FeNO testing as an option for managing patients that are symptomatic despite inhaled corticosteroids (ICS).

2011: American Thoracic Society11

  • Set up the widely used cut-off points for the interpretation of FeNO testing in adults and children (up to 12yo).
  • Jointly endorsed by ACAAI and AAAAI in 2012.
  • For diagnosis: FeNO strongly recommended for the diagnosis of Type 2 airway inflammation in children (up to 12yo) and adults. FeNO also suggested to support the diagnosis of asthma when objective evidence is required.
  • For treatment: FeNO strongly recommended to predict the likelihood of steroid responsiveness in patients with suspected airway inflammation.
  • For management: FeNO strongly recommended for monitoring airway inflammation in patients with asthma. FeNO also strongly recommended to predict ICS responsiveness.

The importance of guidelines

Many national societies have produced asthma guidelines and strategies recognising the role of FeNO testing for:

  • diagnosing airway inflammation and asthma
  • enhancing asthma management through therapy and adherence optimisation, leading to a reduction of exacerbations
  • choosing the right biologic in severe asthma

Countries with national guidelines include: USA, Japan, Italy, China, France, Mexico, Scotland, Spain, Malaysia, Australia...12-22


1. Louis R et al. European Respiratory Society guidelines for the diagnosis of asthma in adults. Eur Respir J 2022; in press. 2. Global Initiative for Asthma (GINA). Global strategy for asthma management and prevention. 2021 update. 3. Khatri SB et al. An official American Thoracic Society clinical practice guideline: use of fractional exhaled nitric oxide to guide the treatment of asthma. Am J Respir Crit Care Med. 2021;204(10):e97-e109. 4. Gaillard EA et al. European Respiratory Society clinical practice guidelines for the diagnosis of asthma in children aged 5-16 years. Eur Respir J. 2021;58(5):2004173. 5. Holguin F et al. Management of severe asthma: a European Respiratory Society/American Thoracic Society guideline. Eur Respir J. 2020;55(1):1900588. 6. Expert Panel Working Group of the National Heart, Lung, and Blood Institute (NHLBI) administered and coordinated National Asthma Education and Prevention Program Coordinating Committee (NAEPPCC) et al. 2020 Focused updates to the asthma management guidelines: a report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. J Allergy Clin Immunol. 2020 Dec;146(6):1217-1270. 7. Larenas-Linnemann D, et al. MIA 2021, Manejo Integral del Asma, Lineamientos para México [MIA 2021, Comprehensive Asthma Management, Guidelines for Mexico]. Rev Alerg Mex 2021; 68(suppl 1):S1-S122. 8. Korean Chromnic Cough guidelines, 2018. 9. FitzGerald JM, et al. Recognition and management of severe asthma: A Canadian Thoracic Society position statement. Can J Respir Crit Care Sleep Med 2017;1:199-221. 10. National Institute for Health and Care Excellence (NICE). NICE guideline. Asthma: diagnosis, monitoring and chronic asthma management. 2017. 11. Dweik RA et al. An official ATS clinical practice guideline: interpretation of exhaled nitric oxide levels (FeNO) for clinical applications. Am J Respir Crit Care Med. 2011;184(5):602-15. 12. Wang Z et al. Agency for Healthcare Research and Quality (AHRQ). The clinical utility of fractional exhaled nitric oxide (FeNO) in asthma management. Comparative Effectiveness Reviews, 197. 2017. 13. Matsunaga K et al; Japanese Respiratory Society Assembly on Pulmonary Physiology. An official JRS statement: The principles of fractional exhaled nitric oxide (FeNO) measurement and interpretation of the results in clinical practice. Respir Investig. 2021;59(1):34-52. 14. Dinh-Xuan AT et al; French Speaking Respiratory Society. Contribution of exhaled nitric oxide measurement in airway inflammation assessment in asthma. A position paper from the French Speaking Respiratory Society. Rev Mal Respir. 2015;32(2):193-215. 15. Larenas-Linnemann D, et al. Consenso mexicano en relación con la fracción exhalada de óxido nítrico (FeNO) en asma 2020 [Mexican consensus on fractional exhaled nitric oxide (FeNO) in asthma 2020]. Rev Alerg Mex. 2020;67(2):S1-S25. 16. Kuo CR et al. Scottish consensus statement on the role of FeNO in adult asthma. Respir Med. 2019;155:54-57. 17. Heffler E et al. Fractional exhaled nitric oxide (FENO) in the management of asthma: a position paper of the Italian Respiratory Society (SIP/IRS) and Italian Society of Allergy, Asthma and Clinical Immunology (SIAAIC). Multidiscip Respir Med. 2020;15:36. 18. Asthma Collaborative Group, Respiratory Group, Pediatrics Branch of Chinese Medical Association. Expert consensus on the detection and clinical application of exhaled nitric oxide in children (2021 edition). Chin J Pract Pediatr 2021;36:417-23. 19. Plaza V, et al. Novedades y otros aspectos destacados de la Guía Española para el Manejo del Asma (GEMA), versión 5.0 [Highlights of the Spanish Asthma Guidelines (GEMA), version 5.0]. Arch Bronchopneumol 2021;57:11-2. 20. Lin J, et al. Chinese expert consensus on diagnosis and management of severe asthma. J Thorac Dis 2018;10:7020-44. 21. Muneswarao J et al. Clinical Practice Guidelines: Management of asthma in adults. Ministry of Health, Malaysia. MOH/P/PAK/354.17. 22. National Asthma Council Australia. Australian Asthma Handbook, Version 2.1. National Asthma Council Australia, Melbourne, 2020.