The test measures several things:
- the amount of air you take into your lungs
- how quickly you can blow it out (spirometry)
- how much air is left in your lungs after you exhale (lung volumes)
- how much oxygen is transported from your lungs to your blood (lung diffusion)
This test is noninvasive, but you are required to put in your best effort. You will be tested by a licensed Pulmonary Lab Technician, who will explain each part of the test to you, and assure that the results represent your best effort. You may or may not also receive a breathing treatment during this test, to see if you respond to a medicine called a bronchodilator. The medicine may give you the ability to exhale more air out, with more force.
You may be asked to repeat some of the tests on subsequent visits as part of your treatment plan.
In order to prepare yourself to do your best on this test, we ask that if you currently use home breathing treatments or personal inhalers, do not use them for at least 8 hours prior to your visit. We also ask that you avoid smoking, chocolate, coffee, tea, and colas or other caffeinated beverages for at least 8 hours as well. Please take all other medications as prescribed.
More Information on Pulmonary Function Testing
A general overview of pulmonary lung function testing, what to expect, and how to prepare, by MedlinePlus Medical Encyclopedia.
A detailed overview of PFTs and what to expect on your visit, by the National Heart, Lung, and Blood Institute.