Patient Information Leaflet

Lung Function Tests

What are Lung Function tests?

Lung function tests are a set of breathing exercises to measure how well your lungs are working. The results will help to understand the cause of your breathing difficulties or symptoms, aid with making a diagnosis and will enable your doctor to monitor your condition.

Most people are able to have these tests safely, but the tests increase the pressure inside your body, so they may need to be delayed or avoided if you have a condition that could be made worse by this. Please contact us prior to your appointment if you have (or have recently had); a chest infection or flare up where antibiotics or steroids are being taken; unstable angina; a heart attack; uncontrolled high blood pressure; or an operation to your head, chest, stomach or eyes.

You will be asked to perform various breathing exercises depending on which tests your doctor has asked for. The tests you may be asked to do are:

  • Spirometry tests check the total amount and speed of the air you can blow out of your lungs, it might be performed with and without an inhaler.
  • Gas transfer is a measurement to assess the lungs’ ability to transfer air into the blood stream.
  • FeNO tests are a simple way of measuring airway inflammation.

Before your appointment

  • Wear loose fitting clothing
  • Do not smoke for 24 hours before the tests
  • Avoid eating a heavy meal two to four hours before the tests
  • Avoid eating nitrate rich food for at least three hours before the tests. Nitrate rich foods include green leafy vegetables (celery, leek, lettuce, and spinach) and beetroot
  • Avoid drinking hot drinks and caffeine an hour before the tests, and avoid alcohol on the day of the tests
  • Do not undertake strenuous exercise or exert yourself at least one hour before your tests

Inhalers and other medication

We ask that you continue to take your normal medication that is not breathing related.

If you use inhalers, please bring each inhaler with you, or write down the names. You may have been prescribed a specific inhaler to bring to the tests, please allow enough time to collect this from your chosen pharmacy prior to your appointment.

If possible, try to avoid using your inhalers for the durations listed below, unless you are breathless and feel you need to use them. If you do use them, please mention it in your appointment.

  • Avoid using long acting once daily inhalers 24 hours before the tests
  • Avoid using long acting twice daily inhalers 12 hours before the tests
  • Avoid using short acting reliever inhalers 6 to 8 hours before the tests

During your appointment

Staff may need to take your height and weight as part of the tests.

The staff will instruct you on what to do during the tests, all the tests involve breathing into a monitor using a disposable mouthpiece, you may be asked to wear a nose clip too.

Feel free to ask any questions you have during your test; we are there to support you throughout.

The tests can take 45 minutes to complete.

After your appointment

Some people may feel dizzy, faint, shaky, sick or tired for a short period afterwards, so you may want to plan to take it easy for the rest of the day. Your doctor will discuss the results of your tests at a future appointment.

Special requirements

All of our patient leaflets are available in large print formats.

If you require additional help or have other accessibility needs, please contact us on 01306 735459