Pulmonary Function Testing Pulmonary Function Tests (PFTs) are a group of breathing tests that measure how well the lungs take in and release air and how well they move oxygen into the blood. They are performed to make measurements of how your lungs and airways function. Results from pulmonary function tests enable your physician or health care provider to evaluate your breathing, make diagnosis, recommend treatment and follow your progress. Your doctor may also schedule you for a Forced Exhaled Nitric Oxide (FENO) test. This test will provide valuable information about airway wall inflammation. During the testing you will be given instructions and encouraged to give your best effort. Your cooperation while performing the test is crucial in order to get accurate results. A poor seal around the mouthpiece of the spirometer can give poor results that can’t be interpreted. Do not smoke before the test or eat a heavy meal. You’ll get specific instructions from our office if you need to stop using any inhaler medications. Please feel free to ask questions during your test.