Fractional exhaled nitric oxide (FeNO) measurements

Fractional exhaled nitric oxide (FeNO) is a measure of airway inflammation. It can be used as part of asthma diagnosis, and to give an indication of how well a person is likely to respond to inhaled corticosteroid therapy. FeNO is commonly measured in specialist clinics; it is not readily available in primary care at the time of writing.