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Mannitol challenge test

Patient information A-Z

Lung function test equipment being used by a person for performing spirometry to assess the response to inhaling mannitol.
Lung function test equipment

About the mannitol challenge test

Why am I having a mannitol challenge test and what is it?

A mannitol challenge test assesses whether the airways are more sensitive than normal. Assessing the sensitivity of your airways can help your doctor to understand the type of conditions that may be affecting your lungs.

What does a mannitol challenge test involve?

The mannitol challenge test involves performing a spirometry breathing test (see the spirometry information leaflet, document ID 102413) to assess your baseline lung function. The next step will involve inhaling an amount of dry powdered sugar before repeating the breathing test. This will then be repeated a number of times with increasing doses of dry powdered sugar. If your airways are sensitive, there may be a decline in your lung function, which may cause you to cough and/or feel tight chested. The test will be stopped if you have a decline of more than 15% from baseline. The physiologist will give you an inhaler and then repeat the breathing test to ensure that you leave the department in the same condition as you arrived. The test typically takes up to 1 hour 30 minutes.

About your appointment


  • You should stop all inhaled medication for at least 12 hours and any antihistamines for seven days prior to your appointment.
  • Please also refrain from smoking, drinking caffeine, and performing vigorous exercise for at least six hours prior to attending the appointment.
  • The test will last up to 90 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.


Inhaling the mannitol may result in you coughing more often during the test. If your lung airways are sensitive, the mannitol will cause them to narrow. This may results in you feeling more wheezy, out of breath or tight chested than when you started the test. The relief inhaler at the end of the test should help to resolve these issues.

All drugs carry at least a small risk of side effects. For mannitol this includes a headache, chest tightness, sore throat, light-headedness, nausea, runny nose, vomiting, or dizziness. Please be aware that although very rare, all medications also carry a risk of allergic reaction.

Due to the nature of the tests and the exertion required, some patients may feel dizzy or faint during testing. 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