In an asthmatic person, the airways can become inflamed. Nitric Oxide is produced at a higher than normal concentration. This can be used as a biomarker of airway inflammation in people with asthma or allergic rhinitis.
The test is very simple to perform in minutes and easy to interpret with a single value reading in parts per billion (ppb). Unlike lung function testing, it requires minimal patient compliance and respiratory effort.
Children as young as 3 years can perform the test.
A positive FeNO reading in conjunction with spirometry and peak flow tests can help confirm a diagnosis of asthma or allergic rhinitis in a patient and/or support ongoing treatment for the disease.