Lung function tests measure how much air your lungs hold and how quickly your lungs can move the air in and out. Spirometry is often the first lung function test that is done. You may also have other tests, such as gas diffusion tests, body plethysmography, inhalation challenge tests, and exercise stress tests. Your doctor will explain which tests you need.
These tests check how well your lungs work. They may also be called pulmonary function tests, or PFTs.
Doctors use lung function tests to find the cause of breathing problems and diagnose lung diseases like asthma or emphysema. You may have lung function tests before you have surgery. Or your doctor may use lung function tests to find out how well treatment for a lung problem is working.
What happens during the test depends on the type of test you have. A respiratory therapist or technician will do the lung function tests.
For most tests, you will wear a nose clip. This is to make sure that no air passes in or out of your nose during the test. You then breathe into a mouthpiece attached to a recording device.
The therapist may urge you to breathe deeply during some of the tests to get the best results.
You may have a blood test to check oxygen and carbon dioxide levels in your blood before, during, or after your lung function tests.
The testing may take from 5 to 30 minutes, depending on how many tests you have.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
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Current as of: May 12, 2017
E. Gregory Thompson, MD - Internal Medicine
& Adam Husney, MD - Family Medicine & Elizabeth T. Russo, MD - Internal Medicine
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