Performing Spirometry Test Make an Appointment Ask a Question Refer Patient You will be asked to place a mouthpiece attached to the spirometer in your mouth. It is important to make a tight seal with your lips so all of the air will go into the spirometer to be measured. You will also wear noseclips to keep air from leaking out of your nose. After breathing normally you will be asked to slowly blow out until your lungs are empty. Then you will take a big, deep breath to fill up your lungs completely. As soon as your lungs are full, you will blow out as hard and as fast as you can until your lungs are absolutely empty. You will be asked to repeat the test until there are three good efforts. This test allows us to measure your: Forced Vital Capacity (FVC) - the amount of air you can force out of your lungs after a maximum inspiration Forced Expiratory Volume in the first second (FEV1) Peak Expiratory Flow Rate (PEFR) - how fast you can blow out the air in your lungs Forced Inspiratory Vital Capacity (FIVC) - the amount of air you can take into your lungs The shape of your Flow Volume Loop (FVC + FIVC) also provides information to your physician Learn more about spirometry testing.