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What is the purpose of this test?


A PFT is a breathing test that tells the doctor about your lung function. The individual lung tests are as follows:

  • Spirometry- measures how well you move air in and out of your lungs and how fast you can blow air out of your lungs.

  • Diffusion- measures how well your lungs deliver oxygen to your blood.

  • Lung Volumes- measure the volume of air you have in your lungs at different stages of your breathing pattern.

  • Airway resistance- measures pressure in your lungs.

Your doctor may only order one of these tests, but most often he/she orders a complete PFT, which includes all four tests. Each test is repeated at least two times to indicate reproducibility.

What preparation is needed for the test?


You may be asked to skip your aerosolized breathing treatment four hours prior to the PFT. Otherwise there is no preparation for the test.

What will happen during the test?

You will sit in a chair in front of a breathing circuit and will be instructed to perform different breathing maneuvers. Some of the breathing maneuvers you will be asked to do include: breath normally, take some deep breaths in and out, blow out forcefully, pant and hold your breath. You will be given a breathing treatment with a medication during the test and then asked to repeat one of the tests following the treatment.

How will I feel during the test?


You may become lightheaded or dizzy at times, but usually there are no other symptoms experienced during the tests.

How long will the test take?


It usually takes about an hour to complete a PFT. The time varies based on which tests the doctor has ordered and how well you can follow the instructions for each test. You may resume your normal activity and medication after the test.

When will I know the results of the test?


Your pulmonologist will interpret or read the exam. The doctor will discuss your results at your next office visit.

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