Lung function tests (Breathing tests)

What is a lung function test?

A “lung function test” is a procedure performed to give us accurate information about your breathing and how your lungs work. 

Why do I need to have this test?

This test provides detailed information about your lungs to your clinical team. This will enable them to provide you with the most appropriate plan. 

What happens during the test?

Before the test starts the Physiologist will explain the test to you in detail and will answer any questions you may have.

The lung function test is painless. It involves a series of breathing tests consisting of breathing and blowing through a mouthpiece connected to special equipment.

The test will take approximately half an hour to one hour depending on the information required.

Important instructions

  • If you are currently taking any inhalers, please stop taking them four hours before the appointment time.
  • Please do not smoke for four hours before the test.
  • Please do not drink alcohol for four hours before the test.
  • Please do not do any vigorous exercise 30 minutes before the test.
  • Please eat and drink as normal.
  • Please do not wear lipstick or nail varnish to the appointment.

Thank you for your cooperation. This will assist us in obtaining accurate information and enable us to provide you with the most appropriate treatment.

Frequently asked questions 

Will I experience any discomfort or side effects?

Some of the breathing tests are tiring, but you will be given time to recover between tests and there are no known side effects associated with this test.

When will I be told the results of my test?

You will usually be told your results at your next clinic appointment, or a letter may be sent to your GP or the doctor who referred you for the test.

What should I wear when I attend for my test?

You should wear normal comfortable clothing.

What will happen if I do not want to have this test?

If you do not attend for this test we will not be able to pass important diagnostic information to the doctors. This may affect the medical treatment that you receive. You can choose to have the test or not.

Reference

Cooper, B, Evans, A, Kendrick, A and Newall, C (2005) Practical Handbook of Respiratory Function Testing: Part 1. Association for Respiratory Technology and Physiology.

© North Bristol NHS Trust. This edition published July 2024. Review due July 2027. NBT002296.

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Lung function tests (Breathing tests)