A pulmonary function test (PFT) is a group of tests that measure how well lungs take in and release air and how well they move gases such as oxygen from the atmosphere into the body’s circulation.
A spirometer is a machine that measures how much air a person exhales, and how quickly. The spirometer records the amount and the rate of air that is breathed in and out over a period of time.
Pulmonary function tests are done to diagnose certain types of lung disease, find the cause of shortness of breath, measure whether exposure to chemicals at work affects lung function, or to check lung function before a surgery.