Bronchial challenge tests

 A bronchial challenge test measures how sensitive your airways are by using a medicine to irritate them to see if they narrow. This can help to diagnose asthma.

It can also be called an airway provocation test or direct challenge test.

If your healthcare professional thinks you may have asthma, they will do some tests like spirometry and FeNO. If these tests do not give a clear result and you still have unexplained symptoms, they may consider referring you to a specialist team for a bronchial challenge test. This can help them to see if you have asthma or not.

The test is suitable for adults and most children over five.

Bronchial challenge tests are not used to monitor asthma once you have an asthma diagnosis.

You should get a leaflet or instructions with your appointment letter. It’s important that you read these carefully, as it will help you to prepare for the test.

You may be asked to:

• stop taking inhalers 12 hours before your test
• stop taking antihistamines 12 hours before your test
• stop smoking for six hours before your test
• stop drinking caffeine for six hours before your test
• avoid intense exercise six hours before your test.

A bronchial challenge test is done in a hospital, but you will not need to stay overnight. The test usually takes up to 90 minutes.

Before the test begins, you’ll be asked to do a simple breathing test called spirometry. This is to check your lung function. If your lung function is not too low, then you can do the bronchial challenge test.

You’ll be asked to breathe in a medicine as a powder or mist through a hand-held device or nebuliser. Then you will do another spirometry test to check if your lung function has changed. If your breathing does not change with the first dose of medicine, you’ll be given a slightly stronger dose. The medicine starts at a very low dose and builds up slowly.

Your breathing will be tested between each dose with spirometry. This is to check if there are any changes in your airways.

If any symptoms are triggered from the test, your specialist will be there to reassure, monitor and treat you with a reliever medicine if needed. Usually your healthcare professional will be able to see if your airways are tightening from your results before you’re able to feel it.

If your breathing gets worse quickly during the test, this may mean your airways are more sensitive. This could mean you have asthma. Your doctor will discuss your results with you and tell you if you need asthma treatments.

If you don’t have a reaction to the powder or mist you breathe in, it’s less likely that you have asthma.