The way to diagnose and manage asthma has changed with FeNO testing.

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NICE has recently published new guidance on asthma diagnosis and monitoring.
The most significant change to the guidance is the introduction of FeNO testing.
If you suspect asthma in an adult patient, a FeNO test should be offered.

NICE guidelines and FeNO:

Key points

A FeNO test should be offered as the first line of investigation for adult patients (17 and over) if a diagnosis of asthma is being considered.
A FeNO test should be considered for children (aged 5 to 16) if there is diagnostic uncertainty following initial assessment.
Regard a FeNO reading of 40ppb in adults and 35ppb in children as a positive test
Asthma should no longer be diagnosed based on clinical symptoms, medical history or spirometry alone; and that a combination of objective tests including FeNO would need to be performed in any case, to support a diagnosis.
The NObreath® FeNO monitor is a highly cost-effective device.

It was one of the devices used in the NICE feasibility study5 during the development of the asthma diagnosis and monitoring guideline.


On 6th February 2020, NHS England announced an update to the GP contract agreement for 2020/21 to 2023/24 with important improvements to the asthma and COPD domains.

The updated contract has now aligned with the current NICE asthma guidance where practices are expected to use a minimum of two diagnostic tests to confirm an asthma diagnosis.
View published article by PCRS on updated Respiratory QOF indicators in the GP contract
Nice Guidelines. Image of Women with Inhaler

Why the change?

According to NICE, incorrect diagnosis of asthma is a significant problem in the UK. The new NICE guidance aims to improve the accuracy of diagnosis, help people to control their asthma and reduce the risk of asthma attacks.

Asthma is a disease that is often challenging to assess as there is no single objective test available to confirm a diagnosis, and as a whole lacks a gold standard.2 Historically, a diagnosis of asthma has been principally based on thorough history taken by an experienced clinician. Multiple studies suggest that up to 30% of adults diagnosed2 with the condition do not have clear evidence of asthma. Some studies have even found that asthma may have been underdiagnosed.
Published evidence in patients with severe asthma suggests that at least 30% of patients are partially or non-adherent with their prescribed medications. Poor adherence was associated with 38% of asthma deaths.3
The introduction of FeNO testing will aid clinicians to make better clinical decisions for patients with suspected asthma.
Map of the UK
Across the UK
million people
are currently receiving treatment for asthma. That’s 1 in every 11 people!4
Image of Costs stacking up
It costs the NHS
per year
to treat and care for people with asthma4
Image of 30% of adults infographic
Studies suggest
of adults
diagnosed with the condition do not have clear evidence of asthma2

Diagnostic algorithms

There are three new diagnostic algorithms. NICE is recommending objective testing with spirometry and FeNO. Click on the tabs below to expand.
Diagnostic Algorithm A: Initial Clinical Assessment (PDF)Diagnostic Algorithm B: Objective tests (Children and young people 5-16) (PDF)Diagnostic Algorithm C: Objective tests (Adults 17 and over) (PDF)

Download NICE guidelines

The full guidance on “Asthma: diagnosis, monitoring and chronic asthma management” was published by NICE on 29th November 2017 and is available

We have provided links below to download the guidelines directly from the NICE website.

NICE guidelines (PDF, 39 pages)
NICE guidelines: Methods, evidence and recommendations

NObreath® FeNO monitor

The NObreath® was one of the monitors used in the NICE feasibility5 study for the development of the new asthma guidelines. It is also recommended in the NICE guidance for measuring FeNO concentration in Asthma (DG12).

It is a highly cost-effective device with low running costs.

Learn More


We have used facts and figures from NICE and other reputable sources to compile the content on this web page about the NICE guidelines. These are referenced in the bibliography below.

2. NICE Guideline NG80. Asthma: diagnosis, monitoring and chronic asthma management. Context section under diagnosis and monitoring.

3. Royal College of Physicians’ National Review of Asthma Deaths (May 2014)

4. Asthma facts and statistics. As 29th November 2017. Asthma UK.

5. NICE Guideline NG80. Asthma: diagnosis, monitoring and chronic asthma management. Appendix Q: Primary Care Implementation Feasibility Report