FENO Testing (Exhaled Nitric Oxide)

A measure of allergic airway inflammation


Nitric Oxide is a gas found to be produced by cells involved in allergic inflammation in the airway. People with allergic airway inflammation therefore generally have higher levels of nitric oxide (NO) in their exhaled breath than others. FENO testing is a non-invasive breath test that measures this nitric oxide in your exhaled breath and gives insight into whether or not allergic airway inflammation is present. FENO testing along with Spirometry can help in the diagnosis of inflammatory airway disease, especially allergic asthma and eosinophilic airway disease. It can also be used to monitor the control of airway inflammation over time on your treatment.

(Due to the patient technique required for this test, it is often not able to be used in children under the age of 7.)

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