Asthma Awareness Month Series Part Four: Performing a FeNO test

Part four: Performing a FeNO test

Performing a FeNO test is quick, easy and non-invasive.(1) Doing a FeNO test is as easy as inhaling and exhaling.

The patient inhales then exhales through the device, guided by the engaging animations on the screen to make sure that they maintain the correct pressure – about the same pressure as blowing bubbles in a drink through a straw. The exhalation lasts for 10 seconds for adults and 6 seconds for children or people with severely reduced lung function, making it accessible for all.(2-4)

The test only lasts about 2 minutes from inhalation to receiving your result, so you can use it to guide clinical decisions there and then.(5,6)

• Interpreting FeNO

According to guidelines by the American Thoracic Society, for adults, a FeNO score of 25 – 50 ppb is in the intermediate range meaning Type 2 inflammation is possible, and a score over 50 ppb indicates Type 2 inflammation is likely.(7) These ranges differ slightly for children under 12, as the guidelines state 20 – 35 ppb is intermediate, but a score over 35 ppb is high.(7)

Check out niox.com for interpreting FeNO.

• Considerations

It is important to ask your patients to avoid eating, drinking, smoking, or doing strenuous exercise for two hours before their test as these factors may influence their FeNO score which could affect treatment decisions.(8) If you’d like to find out how, check out our educational articles on niox.com.

We hope that you have found the information in this series insightful, and if you want to find out more about FeNO and how it can help you and your patients, head to niox.com.

References:

1. Alving K et al. Validation of a new portable exhaled nitric oxide analyzer, NIOX VERO?: randomized studies in asthma. Pulm Ther. 2017;3:207-218.
2. NIOX?. Product Labelling Summary NIOX VERO?. 2023.
3. Donohue JF et al. Characterization of airway inflammation in patients with COPD using fractional exhaled nitric oxide levels: a pilot study. International journal of chronic obstructive pulmonary disease. 2014:745-51.
4. Menzies-Gow A et al. Clinical utility of fractional exhaled nitric oxide in severe asthma management. Eur Respir J. 2020;55(3):1901633.
5. Provenzano B et al. Use of fractional exhaled nitric oxide as a potential predictor of bronchodilator response. Medicine. 2023;102(28):e34073.
6. Loewenthal L et al. FeNO in asthma. Semin Respir Crit Care Med. 2022;43:635-645
7. 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.
8. American Thoracic Society; European Respiratory Society. ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005. Am J Respir Crit Care Med. 2005;171(8):912-30.