Which statement is true regarding a decrease in FENO?

Which statement is true regarding a decrease in FENO?

• A. It indicates decreased airway inflammation
• B. It indicates there is no airway inflammation
• C. It indicates an increase in airway inflammation
• D. It indicates improved gas exchange

Answer: (C)

FeNO is a marker of airway inflammation, especially eosinophilic inflammation seen in asthma. When inflammation is present or worsens, nitric oxide production in the airway epithelium rises, so FeNO goes up. Reducing that inflammation—such as with inhaled corticosteroids or by limiting triggers—lowers FeNO. So a decrease in FeNO signals a reduction in airway inflammation. It doesn’t guarantee there is no inflammation at all, and it doesn’t directly indicate how well gas exchange is working, which depends on other lung factors. In children, tracking FeNO helps assess asthma control and response to anti-inflammatory therapy.

FeNO is a marker of airway inflammation, especially eosinophilic inflammation seen in asthma. When inflammation is present or worsens, nitric oxide production in the airway epithelium rises, so FeNO goes up. Reducing that inflammation—such as with inhaled corticosteroids or by limiting triggers—lowers FeNO. So a decrease in FeNO signals a reduction in airway inflammation. It doesn’t guarantee there is no inflammation at all, and it doesn’t directly indicate how well gas exchange is working, which depends on other lung factors. In children, tracking FeNO helps assess asthma control and response to anti-inflammatory therapy.