Measuring fractional exhaled nitric oxide (FeNO) concentration in asthma

FeNO testing is a method of diagnosing asthma by measuring fractional exhaled nitric oxide (FeNO) in the breath of patients. It aims to improve patient care and outcomes by more effective diagnosis of patients suspected of having asthma. Rollout supported nationally by the AHSN Network as part of the Rapid Uptake Product (RUP) programme.

Eastern AHSN is working with partners across the region to help clinicians diagnose asthma through the use of fractional exhaled nitric oxide (FeNO) testing.

What is FeNO testing?

A fractional exhaled nitric oxide (FeNO) test measures the level of nitric oxide in the exhaled breath and can help differentiate between allergic (eosinophilic) and non-allergic asthma.

The test is non-invasive, easy to perform, and results are often available within seconds. It should be used alongside a patient’s own clinical history and other tests to support a diagnosis of asthma.

Why is this so important?

Over 5.4 million people in the UK suffer from asthma1 and the NHS spends around a billion pounds on asthma annually2, 90% of which goes directly on asthma medication.

Around 30% of patients currently diagnosed with asthma are suspected to have been misdiagnosed3, 4. This means they may be taking inappropriate or unnecessary medication. Measuring FeNO concentration in the patient’s breath helps support a more accurate diagnosis and ensures patients are prescribed the correct medication in the appropriate dosage. It can also be used to monitor a patient’s treatment.

Good adherence to treatment is vital to control symptoms and prevent asthma attacks, yet adherence is generally poor5.

This programme was featured in the AHSN Network Health Innovation Podcast.

How is Eastern AHSN supporting this rollout?

FeNO testing is being supported nationally by the AHSN Network as part of the Rapid Uptake Product (RUP) programme. Across the East of England, Eastern AHSN is convening a range of stakeholders, including commissioners, secondary care NHS trusts industry partners and primary care providers to develop a plan for delivering FeNO testing in the region.

We are working with local integrated care systems and clinical commissioning groups to develop potential funding models and incentives to support uptake. We are also gathering and sharing real world evidence from exemplar sites to evaluate the impact on patient outcomes and cost and operational benefits.

Access resources

Click here to access a number of resources to support the rollout of FeNO testing.

FeNO testing infographic East of England
Did you know?

In 2021/22, FeNO testing identified 34 new asthmatics as well as supporting 45 medication adjustments.

Get involved

If you would be interested in working with us on this project or would like more information, please contact Sarah Curry, Advisor. [email protected].

What are Rapid Uptake Products?

The Rapid Uptake Products (RUP) programme has been designed to support stronger adoption and spread of proven innovations. It identifies and supports products with NICE approval that align with the NHS Long Term Plan’s key clinical priorities, but have lower than expected uptake to-date. Find out more.


  2. Shaw D, Green R, Berry M, et al. (2012) A cross-sectional study of patterns of airway dysfunction, symptoms and morbidity in primary care asthma. Prim Care Respir J 2012; 21: 283-287.
  3. Joanne Kavanagh, David J. Jackson, Brian D. Kent (2019) Over- and under-diagnosis in asthma, Breathe Mar 2019, 15 (1) e20-e27; DOI: 10.1183/20734735.0362-2018:
  5. Connected asthma: how technology will transform care (Asthma UK, 2016)

Share your idea

Do you have a great idea that could make a positive health impact?

Get involved