Lung function tests - Spirometry

Information for patients

Respiratory and sleep physiology

This leaflet provides general information on the lung function tests that you have been referred for. If we need to do other tests that are not described in this information (e.g. Carbon Monoxide monitoring, Oxygen saturation measurement or Exhaled Nitric Oxide) we will discuss them with you on the day.

Your appointment letter will tell you the location, date, and time of your appointment.

What are lung function tests?

Lung function tests look at how well your lungs and airways are working. We compare the results you get with average results for someone of your age, gender and height.

Why do I need to have a Spirometry test?

Your Healthcare Professional has asked that you have these tests to get detailed information about your lungs and airways. This will help the Healthcare Professional to make a diagnosis, decide a treatment plan, or monitor how well current treatment is working. Spirometry is also routinely done as part of a pre-surgical assessment.

How long will the tests take?

Depending on which tests your Healthcare Professional wishes you to have, your appointment will last between 20 and 60 minutes. 

What will I have to do?


This test gives us information about how open your airways are, and the size of your lungs. First, we will ask you to breathe in fully and to blow out in a relaxed way, into a mouthpiece, for as long as you possibly can. This will be done sitting down with a nose peg on. We will then ask you to breathe in fully and to blow out as hard and as fast as possible into a mouthpiece on the lung function equipment, until you are completely empty. We will ask you to do each test a number of times to get accurate results.


This test gives information about how your airways are affected by inhaled medication. You will do the Spirometry test, take an inhaler and then wait between 20 and 40 minutes (depending on the type of inhaler medication) before you do the Spirometry test again.

How do I prepare for the tests?

So that the tests to be carried out successfully please avoid:

  • Short acting bronchodilator/reliever inhalers or nebulisers in the 4 hours before testing - these include Salbutamol, Ventolin, Terbutaline and Bricanyl. Please continue to use any other inhalers and any tablets/medications as normal.
  • Smoking for at least 24 hours before your test as smoking interferes with the test measurements. If you require support stopping smoking please contact Get Healthy Rotherham for free advice and support. Tel. 01709 718720.
  • Exercise in the 30 minutes before testing.
  • Large meals within 2 hours of your appointment time (a snack or a light meal is fine).
  • Caffeine (tea/coffee/ fizzy drinks) for 4 hours before your appointment time.
  • Alcohol in the 4 hours before your test
  • Nail varnish or false nails (if possible)

If you are unsure whether you should use your inhaler or which type of inhaler you have, please contact the department (details at the end of the information). Please also contact the department if you:

  • Have a current or recent chest infection(within 6 weeks prior to your appointment) requiring antibiotic or steroid treatment
  • Have been told you have a collapsed lung, have had a heart attack, stroke or blood clot in the last 6 weeks
  • Have coughed up blood in the last 6 weeks
  • Have had surgery in the last 6 weeks (including eye surgery)
  • Are feeling ill on the day of the test

What should I wear?

You should wear normal, comfortable clothing. Please avoid tight fitting clothes that may restrict your chest movement. You will be asked to remove your shoes in order to measure your height before the tests, so please wear shoes that can easily be removed.

Are there any side effects?

The lung function tests have to be completed with as much effort as possible to get accurate results. Doing the tests can be tiring but you will be given time to recover between tests. There are minimal side effects to completing the tests, however if you have any chest pain or dizziness during testing we will stop and continue only when you feel able to do so.

What happens to my test results?

The results will not be ready straight away as they will need analysing and processing. They will be passed on to the healthcare professional who referred you for the tests and should be available for your next clinic appointment.

What if I cannot attend?

If you are unable to attend the appointment that has been arranged for you, please contact the department on 01709 424572 as soon as possible so that we can organise another appointment for you, and offer your appointment time to another patient on our waiting list.

What will happen if I do not want this test?

You can choose whether or not to have the tests, but if you do choose not to complete them, important information may be missed which may impact on receiving an accurate diagnosis and treatment.

How to contact us

Respiratory and Sleep Physiology 

01709 424572 
Monday to Friday, 8.30am to 4.30pm

Lung function tests - Spirometry - patient information leaflet
Produced by Department of Respiratory and Sleep Physiology, February 2022. 
Revision due: February 2024. Version: 1.0
©The Rotherham NHS Foundation Trust 2022. All rights reserved

Did this information help you?

  • Page last reviewed: 24 January 2023
  • Next review due: 24 January 2024