FeNO

FeNO

 FeNO Testing 

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker used in the diagnosis and management of airway inflammation, particularly in asthma. It measures the concentration of nitric oxide (NO) gas in the exhaled breath, which is produced by various cells in the respiratory tract, including epithelial cells, eosinophils, and macrophages.

The test is simple and easy to do and, alongside other diagnostic tests, can tell you and your asthma team what type of asthma you have.

A FeNO test is suitable for adults and most children over five.

FeNO testing involves having the patient breathe into a handheld device called a nitric oxide (NO) analyzer. This device measures the concentration of NO in parts per billion (ppb) in the exhaled breath. The test is quick, easy to perform, and does not require any special preparation or equipment.

The principle behind FeNO testing is that elevated levels of exhaled nitric oxide are indicative of airway inflammation, which is a hallmark feature of asthma and other inflammatory respiratory conditions. Nitric oxide plays a role in regulating airway tone and inflammation, and increased levels suggest increased inflammation in the airways.

• Diagnosis: FeNO levels can help differentiate between eosinophilic and non-eosinophilic asthma phenotypes. Elevated FeNO levels are suggestive of eosinophilic airway inflammation, which may respond better to corticosteroid therapy.
• Assessment of Airway Inflammation: FeNO levels can provide quantitative information about the degree of airway inflammation, helping healthcare providers assess asthma control and adjust treatment accordingly.
• Monitoring Treatment Response: FeNO levels can be monitored over time to evaluate the response to asthma treatment. A decrease in FeNO levels following treatment initiation indicates a reduction in airway inflammation and improved asthma control.
• Predicting Exacerbations: Elevated FeNO levels have been associated with an increased risk of asthma exacerbations. Monitoring FeNO levels may help identify patients at risk of exacerbations and guide preventive measures.
• Treatment Optimization: FeNO-guided asthma management strategies, such as adjusting corticosteroid doses based on FeNO levels, have been shown to improve asthma outcomes and reduce exacerbations in some patients.

FeNO testing is recommended as part of asthma management guidelines, including those from the Global Initiative for Asthma (GINA) and the National Institute for Health and Care Excellence (NICE) in the UK. It is typically performed in specialized respiratory clinics or asthma centers but may also be available in primary care settings.

Overall, FeNO testing is a valuable tool in the diagnosis, monitoring, and management of asthma, providing objective information about airway inflammation and helping optimize treatment strategies to achieve better asthma control and outcomes.