PULMONARY FUNCTION TEST (PFT)
Pulmonary function tests (PFTs) are a group of tests that measure how well your lungs work. This includes how well you’re able to breathe and how effective your lungs are able to bring oxygen to the rest of your body.Your doctor may order these tests to monitor:
- Chronic obstructive pulmonary disease (COPD)
- Asthma
- Allergies
- Chronic bronchitis
- Respiratory infections
- Lung fibrosis
- Lung cancer
- Weaknesses of the chest wall muscles
Preparation
You should tell your doctor about any over-the-counter and prescription pain medications you’re taking. It’s important that you don’t eat a large meal before testing. A full stomach can prevent your lungs from inhaling fully. You should also avoid food and drinks that contain caffeine, such as chocolate, coffee, and tea, before your test. You should also avoid smoking at least an hour before the test, as well as strenuous exercise before the test. Be sure to wear loose-fitting clothing to the test. You should also avoid wearing jewelry that might affect your breathing. If you wear dentures, wear them to the test to ensure that your mouth can fit tightly around the mouthpiece used for the test. If you have had recent eye, chest, or abdominal surgery or a recent heart attack, you will likely need to delay the test until you have fully recovered.
Procedure
Your PFTs may include spirometry, which measures the amount of air you breathe in and out. For this test, you’ll sit in front of a machine and be fitted with a mouthpiece. It’s important that the mouthpiece fits snugly so that all the air you breathe goes into the machine. You’ll also wear a nose clip to keep you from breathing air out through your nose. You may then breathe normally. Your doctor will ask you to breathe in and out as deeply or as quickly as you can for several seconds. They may also ask you to breathe in a medication that opens your airways. You’ll then breathe into the machine again to see if the medication affected your lung function. Your doctor can learn about your lung volume by measuring the pressure of the volume of air.
