What is a pulmonary function test?

A Pulmonary Function Test (PFT) is a group of tests that measure how well your lungs work. These tests evaluate lung volume, capacity, rates of flow, and gas exchange to help diagnose and monitor lung conditions such as asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders. During a PFT, you may be asked to breathe into a tube connected to a machine that records your lung performance. The results help your healthcare provider determine the cause of breathing problems and guide treatment decisions.