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


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 icon plus

    - 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.
  • How to prepare icon plus

    No preparation is required before your FeNO test.
  • Afterwards icon plus

    You'll be able to resume your normal routine immediately following your FeNO test.

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This content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
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