Pulmonary function tests (PFTs) are a series of breathing tests led by a trained pulmonary technologist, generally done in a hospital or clinic. There are national standards and guidelines to help everyone interpret these tests with the same consistency.

To learn about your lung health, your doctor will want you to have one of many pulmonary function tests done including spirometry, lung volumes, diffusing capacity and arterial blood gases.  Most of these tests are completed by blowing into a tube while sitting in a chair. 

Before having a PFT, you may receive the following instructions:

• Wearing loose clothing which will not restrict the ability to breathe deeply.
• Avoid large meals prior to your test making it more comfortable to breathe deep.
• Don’t use an inhaler on the day of the test, if possible.  

At your appointment:

• The equipment will be set up for you after being cleaned and disinfected, including a clean mouthpiece.
• The technologist will tell you what to do before each test. Listen carefully and follow the coaching from the technologist. If you don’t understand what to do, ask him or her to tell you in a different way