FeNO from Lovemedical WLD801

Why do you need a FeNO test?

FeNO is a noninvasive test for assessing airway inflammatory disease. It’s simple, convenient, and provides accurate and reliable results. It can support in the differential diagnosis and management of other conditions like chronic cough and bronchiectasis. A FeNO test is recommended if you have any of the following:

Recurrent coughing or wheezing, shortness of breath, chest tightness, or other symptoms;
A history of bronchial asthma to evaluate its effectiveness;
Allergic rhinitis.

Clinical Significance of FeNO Testing

Early Screening and Classification of Airway Inflammation
Differential Diagnosis of Common Causes of Chronic Cough
Differentiation between Asthma and COPD
Evaluation of Asthma Response to Anti-inflammatory Therapy
Guiding Asthma Treatment in Children
Supporting Initiation of Inhaled Corticosteroids
Optimising Asthma Treatment During Pregnancy
Guiding Anti-IL-4R Therapy
Supporting Tapering of Oral Corticosteroids
Preventing Relapses and Reducing Hospitalisation

Advantages of FeNO

In chronic inflammatory airway diseases (including asthma), traditional tests such as FEV1, reversibility or provocative testing only indirectly correlate with airway inflammation. FeNO testing offers several advantages for patient care:

The test itself is noninvasive and easily repeatable;
It is relatively easy to use in patients with severe airway obstruction who are difficult to perform with other testing techniques;
FeNO testing provides information about airway disease, complementing traditional clinical testing tools (medical history, physical examination, and pulmonary function tests

Category: Respiratory

Description

Same Clinical Insight — Smarter Cost Efficiency

What is FeNO?

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of type 2 (eosinophilic) airway inflammation¹².

Simple, point-of-care test
Immediate, quantitative result
Repeatable and suitable for routine clinical use¹

Clinical Role of FeNO

FeNO testing is used as part of a structured clinical assessment, alongside history and lung function testing.

Identification of eosinophilic airway inflammation¹²
Asthma diagnosis within guideline pathways³
Prediction of response to inhaled corticosteroids (ICS)¹
Monitoring of airway inflammation over time¹⁴

FeNO should not be used in isolation, but as part of a multimodal assessment³. Use alongside good clinical history.

Guideline Position (UK – 2024 Update)

According to the National Institute for Health and Care Excellence:

Adults

FeNO ≥50 ppb increases the probability of asthma³

Children (5–16 years)

FeNO ≥35 ppb increases the probability of asthma³

FeNO is recommended as part of the objective testing sequence in suspected asthma³

Appropriate Clinical Use

FeNO testing may be considered in patients with:

Suspected asthma with symptoms such as cough, wheeze, or breathlessness³
Uncertain diagnosis after initial clinical assessment³
Ongoing symptoms despite treatment (to support management decisions)¹

Particularly useful where eosinophilic inflammation is suspected¹

Clarification of Scope

FeNO:

Reflects lower airway inflammation¹²
Can support identification of co-existing asthma in patients with allergic symptoms

FeNO does not:

Diagnose conditions such as allergic rhinitis
Replace spirometry or clinical assessment³
Act as a standalone diagnostic test³

Clinical Value

FeNO provides objective insight into airway inflammation, which:

Complements spirometry and symptom assessment¹³
Helps identify patients more likely to respond to ICS¹
Supports more informed clinical decision-making¹⁴

Evidence-Based Benefits

Evidence from clinical studies and systematic reviews shows that

FeNO-guided care:

Can improve asthma management and control⁴
May reduce exacerbations in some patient groups⁴
Supports more targeted use of anti-inflammatory therapy⁴

Outcomes depend on clinical context and appropriate use.

Health Economic Considerations

Health technology assessments indicate FeNO testing:

Can be cost-effective when used within diagnostic pathways⁵
May reduce unnecessary or inappropriate treatment⁵

Cost-effectiveness depends on implementation and patient selection.

Clinical Context

Spirometry → airflow limitation
FeNO → airway inflammation

Used together, these provide a more complete clinical picture¹³

Summary
FeNO is a guideline-supported, non-invasive biomarker that provides objective insight into airway inflammation and supports asthma diagnosis and management when used appropriately.

Lovemedical delivers this same clinical insight with improved cost efficiency.

References

American Thoracic Society — Dweik RA et al. Interpretation of Exhaled
Nitric Oxide Levels (FeNO). Am J Respir Crit Care Med. 2011.
European Respiratory Society — ERS Task Force. Exhaled nitric oxide in
respiratory disease. Eur Respir J.
National Institute for Health and Care Excellence — Asthma: diagnosis,
monitoring and chronic asthma management. 2024.
Petsky HL et al. Exhaled nitric oxide levels to guide asthma treatment.
Cochrane Database Syst Rev.
Harnan SE et al. Exhaled nitric oxide measurement in asthma: health
technology assessment. NIHR HTA.