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Respiratory muscle assessment test

Patient information A-Z

A pressure meter with a nasal bung, used for assessing the strength of a sniff. Person is seated with nasal bung positioned in one nostril.
Lung function test equipment

About the respiratory muscle assessment test

Why am I having a respiratory muscle assessment test and what is it?

A respiratory muscle assessment test assesses whether the muscles which control your breathing are working correctly.

What does a respiratory muscle assessment involve?

Sniff nasal inspiratory pressure (SNIP)

The 'SNIP' involves placing a small bung into the opening of your nostril and sniffing in as hard as possible. We ask you to do this in both nostrils and may repeat the test several times. Depending on the results, we may or may not do two additional tests: 'MIP' and 'MEP'.

Mouth inspiratory pressure (MIP)

The 'MIP' involves wearing a nose peg and breathing through a tube attached to a computer. We will ask you to blow out until your lungs are empty and then suck in as hard as you can against a slight blockage. We may ask you to do this several times.

Mouth expiratory pressure (MEP)

The 'MEP' also involves wearing a nose peg and breathing through a tube attached to a computer. For this test we will also ask you to support your lips and cheeks with your hands. We will ask you to take a big breath in and then blow out as hard as you can against a slight blockage. We may ask you to do this several times.

About your appointment


  • Please take all medication, including using inhalers, as normal (unless otherwise stated in your appointment letter).
  • The test will last approximately 45 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.


Due to the nature of the tests and the exertion required, some patients may feel dizzy or faint during testing. Coughing is also common. Serious complications are rare and risks will be kept to a minimum by your physiologist.

Potential but rare complications

  • Airway narrowing in those with sensitive airways.
  • Heart attack in patients with previous cardiac disease.
  • Sudden changes in blood pressure.
  • Stroke.
  • Collapsed lung.
  • Retinal detachment.

These complications are very rare; you will be questioned by your physiologist prior to the test to determine whether you are at increased risk.

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