A pulmonary function test is relatively simple. A PFT includes a mouthpiece, soft nose clips, a clear, airtight box that measures your airflow, and a small electronic device (spirometer).

Your healthcare practitioner can ask you to do the following before your pulmonary function test:

  • For a short time, stop using your breathing medications.
  • Dress comfortably and loosely so that nothing presses against your chest.
  • Do light activity the day before your test.
  • Tobacco use should be avoided 6 hours before the test.

These precautions will help ensure that you get accurate results from your PFT. Your healthcare practitioner may also advise you not to eat a heavy meal before your PFT and to avoid caffeine.

What happens during pulmonary function tests?

Your procedure might be performed as an outpatient. You return home that same day as a result. Alternatively, it could be carried out as part of an extended hospital stay. The method of execution can vary. It depends on your health and the approaches used by your healthcare professional. The technique will typically proceed as follows:

  • You'll be asked to take off any jewellery, tight clothing, or other items that could interfere with the test.
  • Dentures must be worn during the procedure if you have them.
  • Before the procedure, you need empty your bladder.
  • You'll take a seat. A soft clip will be placed on your nose. This will ensure that you breathe entirely through your mouth rather than your nose.
  • A sterile mouthpiece connected to a spirometer will be provided to you.
  • Using your mouth, you'll create a tight seal over the mouthpiece. You'll be given instructions on how to inhale and exhale.
  • Throughout the treatment, you will be closely monitored for any symptoms of dizziness, breathing difficulties, or other issues.
  • After several testing, a bronchodilator might be administered to you. The tests will then be performed again after the bronchodilator has had time to work.

What happens after pulmonary function tests?

If you have a history of lung or breathing difficulties, you may feel exhausted after the examinations. After that, you'll have time to relax. Your test results will be discussed with you by your healthcare provider.


1) “Pulmonary Function Tests.” Pulmonary Function Tests | Johns Hopkins Medicine, 19 Nov. 2019, www.hopkinsmedicine.org/health/treatment-tests-and-therapies/pulmonary-function-tests.

2) “Lung Function Tests: MedlinePlus Medical Test.” Lung Function Tests: MedlinePlus Medical Test, 9 Sept. 2021, medlineplus.gov/lab-tests/lung-function-tests.