Pulmonary function tests (PFTs) are noninvasive tests that show how well the lungs are working. The tests measure lung volume, capacity, rates of flow, and gas exchange. This information can help your healthcare provider diagnose and decide the treatment of certain lung disorders.

The patient sits in a chair and will be asked to place a soft clip on their nose (This is so all of your breathing is done through your mouth, not your nose). You’ll be given a sterile mouthpiece that is attached to a spirometer. You’ll form a tight seal over the mouthpiece with your mouth. You’ll be instructed to inhale and exhale in different ways. To obtain the optimal results, you must listen carefully and follow the instructions properly (Your full cooperation and effort is very important for the exam to be accurate). In some instances you may be given a bronchodilator after certain tests. The tests will then be repeated several minutes later, after the bronchodilator has taken effect.

You may eat a light meal prior to the exam. You’ll be asked to loosen tight clothing, jewelry, or other things that may cause a problem with the procedure. If you wear dentures, you will need to wear them during the procedure. You’ll need to empty your bladder before the procedure. You will be watched carefully during the procedure for dizziness, trouble breathing, or other problems.

No. If you have a history of lung or breathing problems, you may be tired after the tests. You will be given a chance to rest afterwards.

You may call your doctor to discuss the results.