Pulmonary function tests are a group of tests that measure how well the lungs take in and release air and how well they move gases such as oxygen from the atmosphere into the body’s circulation.
Spirometry measures airflow. By measuring how much air you exhale, and how quickly, spirometry can evaluate a broad range of lung diseases. In a spirometry test, while you are sitting, you breathe into a mouthpiece that is connected to an instrument called a spirometer. The spirometer records the amount and the rate of air that you breathe in and out over a period of time..
For some of the test measurements, you can breathe normally and quietly. Other tests require forced inhalation or exhalation after a deep breath. Sometimes you will be asked to inhale the substance or a medicine to see how it changes your test results.
Do not eat a heavy meal before the test. Do not smoke for 4 to 6 hours before the test. You will get specific instructions if you need to stop using bronchodilators or inhaler medications. You may have to breathe in medication before or during the test.
Pulmonary function tests are done to:
It also can be done to:
The risk is minimal for most people. There is a small risk of collapsed lung (pneumothorax) in people with a certain type of lung disease. The test should not be given to a person who has experienced a recent heart attack, has certain other types of heart disease, or has had a recent collapsed lung.