What are pulmonary function tests (PFT)?

PFTs are a series of breathing tests. These tests measure the size of your lungs, the speed in which air moves through the airways, and the gas exchange in the lungs. These tests give your doctor details about how well your lungs work. Your doctor may choose from many types of breathing tests. The test time may change from 15 minutes to over an hour. The length of test depends on which tests are ordered.

Why do I need to have PFTs?

There are many reasons why your doctor has ordered these tests. The most common reasons are to check:

  • If you have lung disease.

  • The cause and extent of lung problems.

  • The type of treatment for lung problems.

  • The risk for surgery.

How do I prepare for PFTs?

  • Do not exercise or eat a heavy meal for at least four hours before the test.

  • Do not smoke the day of the test.

  • Do not use your inhaler for 24 hours before the test unless you have trouble breathing.

  • Use your breathing medicine if you are short of breath.

  • Wear shoes and clothing for exercise(i.e. walking shoes, sweatpants, shorts). If having an exercise test, you may be walking on a treadmill or riding a bike.

  • We may suggest that you use the bathroom just before the test.

Where do I go for my test?

If your test is at University Hospital, from the parking ramp, you will enter through the main Hospital Entrance. Follow the brown pathway past the “D” elevator lobby to “Clinic Registration” by the Surgical waiting area. After you register, you will go to the Pulmonary Function Lab “Check In” area (Module B6/2). Staff at the information desk can direct you to this location. Please arrive 15 minutes early to register.

If seen at the American Family Children’s Hospital, please park in the Children’s hospital ramp and check in at Registration on the 2nd Floor of the Children’s Hospital. Staff will tell the Pulmonary Function Lab staff that you have arrived.

What happens during the test?

Follow instructions and perform the movements explained to you to get good test results. You will be told how to do each test before you start. The tech will talk you through each test.

Most breathing tests will be done while you are sitting. You will breathe in and out of a mouthpiece to measure your lung function. You may be asked to inhale a mist or spray of medicine into your lungs to see if it improves your breathing.

You may have your blood drawn from an artery to check oxygen and carbon dioxide levels in your blood. This blood test tells how well your lungs use the air you breathe. If blood is drawn from an artery, it is important to keep the site bandaged for 1 hour to reduce any of bruising at the site.

What do I need to do after the test?

You should be able to do your normal routine after the test. Your health care provider will talk with you about your test results when the final report is done.

When to Call

Call if you have any questions before your visit.

Who to Call

UW Pulmonary Function Lab

(608) 263-7000 or (800) 323-8942