Test for asthma

Fractional exhaled Nitric Oxide (FeNO) Test

Using the FeNO test to measure the level of nitric oxide in your lungs can give an indication of asthma.

What is a FeNO test?

A FeNO test is a quick and easy way to measure swelling in the bronchial tubes (airways) of the lungs.

The test may be done to diagnose asthma, check on chronic cough, or to see how well inhaled corticosteroid (ICS) treatment is working if you have already been diagnosed with asthma.

Need to know

What happens during the test?

Lung function tests usually take place in a consultation room or lung function laboratory area.

You'll be asked to sit down for the test.
You'll be asked to breath in as fully as possible and blow out at a steady pace for about 10 seconds.
The test normally takes about 5 minutes.