Pulmonary Function Tests

Pulmonary Function Tests

Pulmonary function tests (also called lung function tests) help measure how well your lungs are working. The tests measure the amount of air you breathe out (exhale) and how long it takes for you to exhale completely. These tests are done to diagnose lung conditions such as asthma and COPD. They may be done before and after you take certain medications. They may also be used to find out whether your shortness of breath gets worse with exercise. Over time, pulmonary function tests can help you and your healthcare practitioners see how well your treatment is working.

Your Experience

A complete pulmonary function test has 3 parts. You may be given the entire test or only certain parts. The entire test is painless and can last 45–90 minutes. If you get tired, you can take a break between test sections.

Before Your Test

• Follow any instructions you are given to prepare for the test. Otherwise, your test may be canceled
• Avoid smoking for 12–24 hours before the test, or stop as directed
• Stop taking your breathing medication 6 hours before the test
• Avoid caffeine and eat only a light meal