A first port of call for any FeNO related questions. If you can't find what you're looking for here feel free to contact us and we'll do our best to answer your query.
Do we need to do FeNO? What does it add?
FeNO is recommended as part of the NICE asthma diagnosis guideline. It is also an option for asthma diagnosis in QOF.
What FeNO adds is another dimension to assessing asthma. There are different types of asthma which behave differently and respond to different treatments.
A high FeNO level helps inform not only the diagnosis but the type of asthma someone has – a high FeNO indicates eosinophilic asthma and is more likely to respond to inhaled corticosteroids. With 30% of cases with asthma potentially mis-diagnosed (and many more underdiagnosed) it is important that we are as certain about an asthma diagnosis as possible. This means that the patient gets the treatment that they need for their chest symptoms and doesn’t receive unnecessary and potentially harmful treatments when they are not needed.
Who can perform FeNO? Is there much training involved?
Anyone with appropriate training can perform a FeNO test on a patient.
We have worked with e-learning for Health (part of Health Education England) to develop 2 learning modules – one for healthcare professionals performing FeNO tests on patients, and one for clinicians interpreting the results. Both take less than 30minutes to complete.
The manufacturers also offer training in their specific machines to support teams that are starting to use FeNO.
Should Feno be based in a practice, PCN or a diagnostic hub?
In reality, this varies. There are many examples of practices and PCNs using FeNO to support the management of their patients. FeNO will be an important part of diagnostic hubs too.
Is FeNO useful apart from in diagnosis?
FeNO is useful for diagnosing untreated eosinophilic inflammation. One of the diagnostic difficulties we have is whether a patient with a diagnosis of asthma with new or persistent symptoms needs their medication adjusting. A FeNO level can help give the clinician and the patient confidence that there is eosinophilic inflammation present that is currently untreated. This may require better adherence, better inhaler technique or a more effective dose of corticosteroid therapy.
What are the benefits of FeNO to patients? To a practice/PCN?
A FeNO test can give the patient more certainty about the accuracy of their diagnosis and the likely impact of their treatment.
Greater accuracy of asthma diagnosis, and asthma phenotype helps prevent patients end up on the wrong treatment pathway. It prevents patient being given the wrong label and exposed to unnecessary (costly and potentially harmful) medications.
What does a high FeNO mean?
A high FeNO level means that there is untreated eosinophilic inflammation present. This increases the likelihood of a correct asthma diagnosis and suggests that the patient will respond to corticosteroid medication. It is crucial that a FeNO reading is not assessed in isolation. It should be used in conjunction with a detailed clinical history, examination and other tests such as spirometry.
What does a normal/low FeNO mean?
A normal or low FeNO means that there is currently no untreated eosinophilic inflammation present. This may be that the patient is already on some treatment that suppresses the inflammation, that they have a type of asthma that does not involve T2 (eosinophilic) inflammation or that they have asthma but the inflammation is currently in remission.
Where can I find out more about the devices?
There are two suppliers who have NICE approval (DG12) – Cricassia and Bedfont.
Our products specific page on the FeNO toolkit provide you with details on each product along with contact details for each supplier.
The AHSN has also created a comparison document, comparing the two products.
There are other suppliers of FeNO devices (e.g. Bosch Vivatmo Pro), however these are not currently part of the National FeNO programme.
Is FeNO considered Non-AGP?
The Association for Respiratory Technology and Physiology (ARTP) have published guidance which states FeNO testing is low risk of being aerosol generating. Spirometry is listed as high risk of being aerosol-generating which means there is an opportunity for FeNO to be used more as it can adapt to the current health climate.
What is eosinophilic asthma?
An estimated 40% of people with severe asthma are diagnosed with a specific type of severe asthma called eosinophilic asthma. This is asthma driven by high levels of a type of white blood cell called eosinophils. If you have high levels of eosinophils in your blood it can cause the airways to become inflamed, leading to asthma symptoms and asthma attacks. See Asthma UK - How is severe asthma diagnosed?
"We have seen positive results with patients who claim to only have hayfever or seasonal wheeze, despite it being winter and no current symptoms" Do you have any advice?
When interpreting FeNO, it is important to consider the result in the context of the history and examination and in combination with a measure of airflow obstruction (especially when diagnosing/excluding asthma). When considering asthma as a diagnosis, consider that asthma is like a jigsaw - the more bits that you have, the clearer the picture will be.
A high FeNO level shows that there is some eosinophilic inflammation in the airways.
If there are no other features of asthma, the FeNO may be coming from the nose (i.e. resulting from hayfever). If the hayfever is treated, the FeNO test result should be suppressed. If not, then the advice would be to re-visit the lungs as a possible cause of the high FeNO.
If there are other features of asthma from the history, examination and measures of airflow obstruction then start on an inhaled corticosteroid and review in a couple of months. Test to see if any chest symptoms, FeNO and airflow obstruction improves.