Understanding FeNO

Nitric oxide (NO) is a gas produced when inflammation occurs in your body, and FeNO is a simple test that measures how much NO you exhale.

People with allergic asthma often have inflamed bronchial tubes (airways). As a result, they exhale higher levels of NO than people without asthma.

FeNO has been proven useful in both diagnosing and managing asthma. For example, if results of a FeNO test indicate that you have increased inflammation in your bronchial tubes, you can start treatment to prevent asthma attacks. FeNO can also be used to guide treatment in patients who already have been diagnosed with asthma. FeNO can provide an extra layer of information for you and your doctor to help you manage your asthma effectively and avoid worsening symptoms. The test can improve the level of control you have over your asthma.