Performing the Routine Pulmonary Function Test 

1. You will be seated in a clear plexiglass booth with your mouth on the mouthpiece and noseclips on your nose
2. You will breathe normally and then a shutter will close. The shutter is closed for a second while you continue to breathe normally against the shutter
3. The shutter opens and after breathing normally you will be asked to slowly blow out until your lungs are empty
4. Then you will take a big deep breath in filling up your lungs completely
5. As soon as your lungs are full, you will blow out as hard and as fast as you can until you are absolutely empty
6. You will then take a breath in and come off of the mouthpiece
7. The door will be opened until you are ready to do another effort
8. You will be asked to repeat the test until there are three good efforts, which are repeatable

This test allows us to measure:

• Lung volumes - Thoracic Gas Volume (TGV) / Functional Residual Capacity (FRC)
• Total lung capacity (TLC)
• Expiratory reserve volume (ERV)
• Inspiratory capacity (IC)
• Inspiratory reserve volume (IRV)
• Residual volume (RV)
• Airways resistance (Raw/Sgaw)
• Spirometry at absolute lung volumes (FVC, FEV1 and PEFR)

This chart shows the measurements made during the test.

Learn more about the routine pulmonary function test.