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Impulse oscillometry test

Patient information A-Z

Lung function test equipment being used by a person undergoing impulse oscillometry. The person breathes via a mouthpiece that has a small speaker on top. A physiologist holds the person's cheeks.
Lung function test equipment

About the impulse oscillometry lung function test

Why am I having an impulse oscillometry test and what is it?

Impulse oscillometry is a test that uses sound waves to measure how much resistance there is to the normal movement of air in and out of your lungs when you are breathing at rest. The test is performed for either diagnostic or monitoring purposes. It can be performed on people of all ages from five years upwards.

What does impulse oscillometry involve?

This test involves breathing normally through a tube attached to a small speaker. We will ask you to sit, and put a peg on your nose. A physiologist may hold your cheeks from behind to ensure a good seal on the tube with your lips. While breathing normally for 30 seconds, sound waves created by the small speaker attached to the mouthpiece will be sent into your lungs. You may feel a slight pressure when you breathe. We may ask you to do this several times.

About your appointment


  • Please take all medication including inhalers as normal (unless otherwise stated in your appointment letter).
  • The test will last approximately 10 to 30 minutes.

If you cannot attend your appointment

If you need to rearrange your appointment, or no longer need an appointment, please call us on 01223 217065 at the earliest opportunity. Reallocating appointments helps us to reduce waiting times.

What if I am unwell prior to the appointment?

Please call us on 01223 217065 if you:

  • have had a recent chest infection, or
  • are currently on a course of antibiotics, or
  • have just finished a course of antibiotics for your chest

It may be inappropriate to perform the test at this time and your appointment may be rescheduled.

If you are unwell, please inform us at the earliest opportunity. If you are unwell on the day of the appointment, please still call and let us know as this will allow us to rearrange your appointment for a more suitable time.

Who will be present at my appointment?

Cambridge University Hospitals NHS Trust (CUH) is a teaching hospital and so there may be occasions when a student or staff member accompanies your physiologist. We will, however, always seek your permission first.


You will be asked for consent to perform tests during your appointment. You will also have an opportunity to ask questions before you give consent. In the unlikely event there are risks related to the test, these will be discussed with you before the test starts.

Test results

After your appointment, your test results will be sent to your referring consultant, who will then contact you to discuss the results and the next steps in your treatment.


Impulse oscillometry carries a very low risk as it involves just breathing normally. Very rarely, however, it may cause airway narrowing in those with sensitive airways. If you are known to have sensitive airways please bring your reliever inhaler for use after the test.

Contacts/ Further information

If you are unclear about any of the information provided in this leaflet or have any other questions then please do not hesitate to contact the Lung Function Department at Addenbrooke’s Hospital on 01223 217065 or Clinic 2A on 01223 216645.

Our opening hours are Monday to Friday from 08:30 to 16:30.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151