Pulmonary Function Testing (PFT) is a group of tests that measure how well the lungs are working. These tests assess lung volume, capacity, and the flow of air in and out of the lungs. PFTs help diagnose conditions like asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders. During a PFT, patients may be asked to breathe into a device called a spirometer. This device records the amount of air inhaled and exhaled, as well as how quickly air moves in and out. The results help doctors evaluate lung function and determine appropriate treatment options.