If you are at risk for asthma, emphysema, COPD, or other lung-related illnesses, your doctor may ask you to undergo pulmonary function testing. Pulmonary function tests are diagnostic services that measure how well your lungs are working. The results help your medical team determine how to treat you safely and effectively. The series of tests can be daunting, but they're not so bad once you know what to expect.
A Trip to The Lab
Pulmonary function tests use specialized equipment, so they're usually not available at your regular doctor's office. Your doctor should recommend a nearby hospital or clinic. Because the tests consist of a few separate procedures, the amount of time they take varies. A complete pulmonary function test takes about 45-90 minutes. Naturally, if your doctor only wants you to take a specific test, your appointment won't take as long.
Before the Tests
If you smoke and/or take breathing medications, the clinic will instruct you to temporarily quit both for a set amount of time before your appointment. To keep your results accurate, you'll also want to avoid heavy meals, caffeine, and strenuous exercise on the day of your tests. To be most comfortable, consider wearing loose clothing.
While there exists a range of pulmonary function tests, there are three typical procedures. They measure how much you inhale/exhale, your lung capacity, and how well your lungs move oxygen to your blood, respectively.
Spirometry: A technician will put a clip over your nose to seal your nostrils. While seated, you'll breathe as hard as you can into a mouthpiece. The technician will have you repeat the test several times to ensure accuracy.
Plethysmography: Again, you'll have a clip over your nose. You'll sit in a glass box similar in size to a telephone booth and breathe into a mouthpiece for about three minutes.
Lung Diffusion: With a clip over your nose, you'll breathe in a harmless gas through a mouthpiece. After holding your breath for about ten seconds, you'll exhale back into the mouthpiece.
Long, but Low-Risk
While pulmonary function testing is safe, it can be tiring due to the sheer length of time you're breathing into tubes. The greatest risk is that you may get a headache or become dizzy from breathing deliberately. Luckily, your technician can help you combat this by allowing you to rest in between tests. If small spaces make you anxious, you may be nervous during plethysmography. Keep in mind that you'll be able to see through the transparent box, and the test is relatively short.