Fractional exhaled nitric oxide measurement / FeNO

About FeNO Testing

Fractional exhaled Nitric Oxide (FeNO) testing is a quick and easy way to measure inflammation (swelling) in the bronchial tubes of the lungs.

The test may be done to diagnose asthma, to evaluate a chronic cough or to see how well inhaled corticosteroid treatment is working in a child who has already been diagnosed with asthma.

The test is done by having your child take a large breath and then breathe out very slowly into a tube connected to a computer. 

Your child will be asked to repeat the breaths several times to get an accurate measurement.

No preparation is required before FeNO testing.

The FeNO test takes a total of about 15 minutes. 

Your child may resume a normal diet and activities afterwards.

A parent’s/guardian’s role

During the FeNO Test:

The most important role of a parent or guardian during the test is to help your child stay calm and relaxed. The best way to help your child stay calm is for you to stay calm.

You may stay near your child. 

Feel free to ask any questions, but please ask them before or after the test.

After the FeNO Test:

Your child may resume normal activities immediately, unless otherwise directed by the doctor. There are no side effects from FeNO testing.