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About FeNO

FeNO (fee-no) stands for fractional exhaled nitric oxide and it can be tested with a simple desktop device at the point-of-care.1 Knowing the level of nitric oxide in a patient’s breath can help healthcare professionals assess the amount of Type 2 airway inflammation in the lungs.1 This type of inflammation is responsible for up to 90% of asthma cases.2,3 FeNO testing results can therefore help improve asthma care by indicating how likely someone is to have asthma and whether treatment is working for those who already have a diagnosis.4-7 A high FeNO level means asthma is seven times more likely.8

About FeNO testing

Performing a FeNO test feels like gently blowing bubbles through a straw into a drink. Almost everyone can do it, including children and patients with reduced lung function.4,9,10 The test itself takes 10 seconds for adults and six seconds for children if they can't manage a 10-second exhalation. The test is simple, immediate and non-invasive, and the device shows the patient’s FeNO score in about a minute.9,11

Find a FeNO Test

Thousands of misdiagnosed patients either receive unnecessary asthma treatment or don’t receive care when they really need it.

Patient and doctor performing a FeNO test

This image is of a patient and a doctor. The patient is performing a FeNO test in a typical consultation setting under the supervision of a doctor.

Patient performing a FeNO test

This image is of a patient performing a FeNO test in a clinical setting

How to perform a FeNO test

This 3 minute animated video explains the process of how to perform a FeNO test.

The Independent

Asthma misdiagnosis is relatively common, yet one quick, non-invasive test can help.

The Guardian

Helping to make asthma care simple with a breath test.

The Mail on Sunday

In 2023, the benefits of FeNO testing featured in a story run by the Mail on Sunday.

Get in touch

For any media enquiries, please use our contact form below or email us at media@fenoandasthma.com

Supporting evidence:

1. Busse WW et al. Baseline FeNO as a prognostic biomarker for subsequent severe asthma exacerbations in patients with uncontrolled, moderate-to-severe asthma receiving placebo in the LIBERTY ASTHMA QUEST study: a post-hoc analysis. Lancet Respir Med. 2021;9(10):1165-1173.
2. Heaney LG et al. Eosinophilic and noneosinophilic asthma: an expert consensus framework to characterize phenotypes in a global real-life severe asthma cohort. Chest. 2021;160(3):814-830.
3. Maspero J et al. Type 2 inflammation in asthma and other airway diseases. ERJ Open Research. 2022;8(3).
4. Menzies-Gow A et al. Clinical utility of fractional exhaled nitric oxide in severe asthma management. Eur Respir J. 2020;55(3):1901633.
5. Price DB et al. Fractional exhaled nitric oxide as a predictor of response to inhaled corticosteroids in patients with non-specific respiratory symptoms and insignificant bronchodilator reversibility: a randomised controlled trial. Lancet Respir Med. 2017;6(1):29-39.
6. Hanania NA et al. Measurement of fractional exhaled nitric oxide in real-world clinical practice alters asthma treatment decisions. Ann Allergy Asthma Immunol. 2018;120(4):414-418.
7. Sabatelli L et al. Cost-effectiveness and budget impact of routine use of fractional exhaled nitric oxide monitoring for the management of adult asthma patients in Spain. J Investig Allergol Clin Immunol. 2017;27(2):89-97.
8. 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.
9. Alving K et al. Validation of a new portable exhaled nitric oxide analyzer, NIOX VERO®: randomized studies in asthma. Pulm Ther. 2017;3:207-218.
10. Donohue JF et al. Characterization of airway inflammation in patients with COPD using fractional exhaled nitric oxide levels: a pilot study. International journal of chronic obstructive pulmonary disease. 2014:745-51.
11. Smith AD et al. Use of exhaled nitric oxide measurements to guide treatment in chronic asthma. N Engl J Med. 2005;352(21):2163-73.

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