PFTs (pulmonary function tests) are noninvasive tests that determine how well the lungs are working. The tests assess lung volume, capacity, flow rates, and gas exchange. This information can assist your healthcare provider in diagnosing and treating certain lung disorders.

Spirometry, a painless test that can be performed in a doctor’s office, hospital, or specialized PFT lab, may be part of your PFTs. Spirometry is particularly useful in the diagnosis of asthma and COPD.

This is because it measures how much air you can expel from your lungs after taking a deep breath and how quickly you can do so. You will sit upright in front of a spirometry machine with a plastic mouthpiece for this test.

The mouthpiece must fit snugly so that all of the air you breathe enters the machine. You’ll also be wearing a nose clip to prevent you from breathing through your nose. The respiratory technologist will show you how to breathe properly for the test.

They’ll instruct you to take a deep breath in, then exhale as forcefully and quickly as you can until your lungs are empty. You may also be asked to inhale a medication that helps open your airways. After that, you’ll take another deep breath and exhale into the machine to see if the medication improved your lung function.