Important Safety Information | NIOX VERO® User Manual (PDF)

For UK Healthcare Professionals Only



A safe and easy test to instantly transform your asthma care

Nobel Prize-Winning Science

An animated image of a Nitric Oxide (NO) molecule

FeNO stands for fractional exhaled nitric oxide (NO). NO is a molecule produced by the lungs that can be measured in exhaled breath. The discovery of NO in medicine was a real breakthrough, leading to a Nobel Prize in 1998.

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An animated image of a Nitric Oxide (NO) molecule

Asthma: it's about inflammation

Asthma is a chronic disease, traditionally diagnosed with tools that show if the lungs are obstructed. However, asthma is actually an inflammatory condition of the airways.1

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4 images detailing the asthma pathway - 1. Airway inflammation 2. Swollen molecules 3. Narrower Bronchi 4. Obstruction
A patient holding a NIOX VERO Breathing Handle performing a FeNO test

See inflammation more clearly

Understanding the level of inflammation with FeNO can lead to improved asthma care. FeNO levels are elevated in asthma and can provide healthcare professionals with the opportunity to see inside a patient’s lungs at the point-of-care.

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More accurate diagnosis

With half of asthma cases misdiagnosed, lung function testing is not enough to make a decision.2 Asthma diagnosis is 7x more likely with a high FeNO level.3

This is Lucy

A hypothetical asthma patient reflecting typical clinical experience

Hypothetical patient reflecting typical clinical experience

She gets breathless when she runs and occasionally at night. Lucy made an appointment to see her doctor to understand what was going on. The doctor performed routine lung function testing and would have ruled out asthma. However when Lucy performed a FeNO test, the result was 73.ppb, indicating airway inflammation. This suggests that Lucy may have asthma.

Hypothetical patient reflecting typical clinical experience

Better management

A high FeNO level indicates a greater risk of exacerbation. Using FeNO testing as your asthma risk estimator can help reduce exacerbations by up to 50%.4

This is Victor

A hypothetical asthma patient reflecting typical clinical experience

Hypothetical patient reflecting typical clinical experience

He has had asthma since the age of 3 and is prescribed an inhaled corticosteroid. Victor still experiences exacerbations and recently visited his doctor. The doctor wanted to check whether Victor was using his inhaler properly and offered him a FeNO test. Victor had a FeNO level of 163.ppb, showing he is non-adherent to his medication and at risk of severe exacerbations. Seeing this number showed Victor how bad the situation actually was. As part of his asthma management plan, Victor tested his FeNO regularly with the aim of reducing his FeNO to a normal level. Seeing his FeNO level reduce at every appointment motivated Victor to keep taking his medication. Victor’s FeNO is now 24.ppb, his inflammation is under control and he has not had an asthma attack in the last year.

Hypothetical patient reflecting typical clinical experience

Why measure FeNO?

FeNO testing is the most convenient way to assess airway inflammation at the point-of-care.


One test, one number. Airway inflammation in a single FeNO value.


Performing a FeNO test takes less than two minutes - quicker than making a cup of coffee.


Taking a FeNO test is as simple as inhaling and exhaling: no blood, sweat or tears required.

How to measure FeNO

Your patient performs the test by inhaling and exhaling into the NIOX VERO® breathing handle. After approximately one minute you are presented with a FeNO level. Check this value with internationally recognised cut-off points to decide your next treatment steps.5

Interpreting FeNO →     FeNO Guidelines →
An animated picture of a face and a NIOX VERO Breathing Handle


An animated version of NIOX VERO® displaying a FeNO test result on-screen


An animated picture of an inhaler


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Learn more about the gold standard FeNO testing device.6

Not only good for people, good for budgets

Studies have shown that FeNO testing is a cost-effective way to improve patient outcomes. Adding FeNO to the treatment algorithm can considerably reduce costs and improve quality of life when used in combination with current treatment guidelines.

Thousands of healthcare professionals around the world are enjoying the economic and clinical benefits of FeNO testing with NIOX VERO®.

Read our comprehensive review of health economics data about FeNO testing
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Find and select your practice below to see funds your practice could access
by including FeNO testing in your asthma management algorithm.

FeNO can help you:7

Be more confident with asthma diagnosis

Speed up treatment decisions

Avoid unscheduled visits

Optimise ICS therapy and adherence

Reduce potentially severe exacerbations

Get started with NIOX VERO®

Join the thousands of healthcare professionals who have already performed over 50 million FeNO tests with NIOX®, and improve patient outcomes.

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1. Global Initiative for Asthma (GINA). Global strategy for asthma management and prevention. 2021 update. 2. Kavanagh J et al. Over- and under-diagnosis in asthma. Breathe (Sheff). 2019;15(1):e20-e27. 3. 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. 4. Petsky HL et al. Tailoring asthma treatment on eosinophilic markers (exhaled nitric oxide or sputum eosinophils): a systematic review and meta-analysis. Thorax. 2018;73(12):1110-1119. 5. 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. 6. NIOX®. Data on File; MKT-DOF-007. 2023. 7. Menzies-Gow A et al. Clinical utility of fractional exhaled nitric oxide in severe asthma management. Eur Respir J. 2020;55(3):1901633. 8. NIOX®. NHS England Asthma data 2022 (AST001). QOF database. Available at; Accessed; May 2023.

* Hypothetical patients