Last Updated 05/11/2020
Authors:Lana Alghothani, MD; Ellen Becker, PhD, RRT, RPFT, AE-C, FAARC; Nitin Bhatt, MD; De De Gardner, DrPH, RRT, FCCP; Mary Hart, RRT, MS
About Spirometry Tests
Spirometry is the most common type of breathing or pulmonary function test. This test measures how much air you can breathe in and out of your lungs, as well as how easily and fast you can blow the air out of your lungs.
Your health care provider may do a spirometry test if you have symptoms like wheezing, shortness of breath, or a cough. This test can help diagnose problems such as asthma and chronic obstructive pulmonary disease (COPD). It can also be done to check lung function before a surgery.
If you have a lung condition, spirometry may be done to determine if your condition is getting better or worse. The results help health care providers determine whether your medications are helping you. Spirometry can be done in the provider’s office or in a special pulmonary function testing lab.
What to expect
On the day of your test, you may be asked not to use certain inhalers or medications. Wear loose-fitting clothing, and avoid big meals before testing.
These tests are not painful. They are performed by a pulmonary function technologist. The tests are repeated several times to make sure the results are accurate. On the day of your test:
- Take your daily medications prior to testing unless told otherwise.
- Do not smoke for at least 6 hours before your test.
- If you use a quick-reliever inhaler as needed, do not use it for 6 to 8 hours before your test, if possible.
- Follow all instructions your health care provider gave you.
During the test, you will be sitting. A clip may be placed on your nose, and you are given a plastic or cardboard mouthpiece connected to the spirometry machine. You place your lips tightly around the mouthpiece. Then you will be asked to take in as big and deep a breath as possible and blow out as hard and fast as you can. This maximum effort is very important. Testing will be repeated at least three times to get the best and most consistent results.
The technologist may give you a medicine to help open your airways and repeat the test to see if the medication improves your breathing.
The testing takes about 30 to 45 minutes.
Understanding the results
Spirometry will give your health care provider information about why you may have a cough, shortness of breath, or noisy breathing. It will also help diagnose certain lung problems. After the test, you can return to your normal daily activities.
Normal values are calculated based on your age, height, race, and gender. If a value is abnormal, a lung problem may be present. Sometimes, a person with healthy lungs may have a breathing test value that is abnormal. Your provider will explain what your test results mean.
Depending on the results of the test, your provider may prescribe inhalers or other medicines to help improve your breathing. The testing may be repeated at future visits to monitor your breathing condition.
What are the risks?
During the test, breathing fast and hard can make you feel tired, dizzy, or light-headed; cause coughing; or lead to chest tightness or pain. Tell the technologist if you have any discomfort.
Tell your provider if you have:
- Had a heart attack within the past month
- Had recent eye, chest, or abdominal surgery
- A collapsed lung
If you had any of these, your provider may wait until you recover before doing the testing.
Special steps are taken to avoid spreading germs between patients who use the same lung function equipment. The technologist will change mouthpieces and clean the equipment between patients. Special filters are also used to prevent the spread of germs.
If you have questions about this test, ask before the test starts.