Spirometry is a simple breathing test that is used to diagnose and monitor lung problems. Discover how it's done.

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Picture of doctor and patient Spirometry

What is spirometry?
Spirometry is commonly done to see how well your lungs work. A device called a spirometer is used to measure how much air the lungs can hold and how well the respiratory system is able to move air into and out of the lungs.

Why would I need a spirometry test?
This test is used to determine the cause of shortness of breath or to rule out any kind of obstructive disease that blocks breathing or restrictive disease that limits the expansion of the lungs. Spirometry is most often used to diagnose and monitor lung problems such as chronic bronchitis, emphysema, pulmonary fibrosis, chronic obstructive pulmonary disease (COPD), and asthma.

Spirometry is also used to monitor how well medications for lung problems are working and to check breathing ability before surgery.

How is spirometry performed?
A spirometer consists of a mouthpiece and disposable tubing connected to a machine. The machine records the results and displays them on a graph.

First you inhale deeply, closing your mouth tightly around the tube. Then you exhale through the tubing while measurements are taken. Some test measurements are obtained by normal breathing, and other tests require fast, forceful breathing. The volume of air inhaled or exhaled and the length of time each breath takes are recorded and analyzed.

Nose clips are usually used to make sure air is only coming out of the mouth. Sometimes a test will be repeated to get the best and maximum effort. Often, the tests are repeated after a person takes a medication called a bronchodilator that opens the airways of the lungs.

A spirometry test can take anywhere from 5 minutes to a half an hour. It depends on the types of breathing tests being measured.

What are the risks of spirometry?
The risks of spirometry are minimal. Because the test involves forced and rapid breathing, some people may have temporary shortness of breath.

Spirometry should not be done if you've had chest pains, a recent heart attack, or serious heart disease.

How should I prepare for spirometry?

  • Do not eat a heavy meal before spirometry testing.
  • Quit smoking. If you do smoke, avoid smoking for 4 to 6 hours before the test.
  • Do not drink alcohol for at least 4 hours before the test.
  • Empty your bladder right before testing.
  • Your doctor will tell you if you need to avoid medications such as bronchodilators or inhalers before the test.
  • Sometimes, medication may be inhaled prior to the test to see how well the person responds to medication.
By Louis Neipris, MD, Staff Writer
Created on 11/14/2001
Updated on 04/25/2011
  • American Thoracic Society. Patient information series: pulmonary function tests.
  • National Heart Lung and Blood Institute. What are lung function tests?
  • American Association for Respiratory Care. Spirometry.
Copyright © OptumHealth.
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