If you have Asthma or are undergoing’s tests to diagnose Asthma you may have heard about the FeNO test. Fractional exhaled nitric oxide (FeNO) is a test used to diagnose asthma by measuring your breath. The test is simple and easy to do and, alongside other diagnostic tests, can tell you and your asthma team what type of asthma you have. 

FeNO is useful to help you build a better understanding of your asthma and to manage it with the support of your asthma team. The FeNO test measures inflammation in your airways. If the inflammation is not treated it can cause life threatening asthma attacks. 

By knowing what kind of asthma you have, you can: 

> Understand your medication better 

> Recognise when your medicines are working well 

> Avoid life threatening asthma attacks. 

The FeNO test is safe and easy to do for adults and children. You will take a big breath in and then gently breath out through the filtered mouthpiece into a small portable device for approximately 10 seconds. The test is much easier to do than other asthma tests such as spirometry or peak flow. The device shows the reading on its screen. 

You can download this PDF. It contains information about FeNO and how to prepare for the test to ensure it is effective.

You can also find more information by visiting the Asthma & Lung UK website.