Spirometry

Spirometry is the most common type of pulmonary function or breathing 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 the blow the air out of your lungs.

Your doctor may order spirometry if you have wheezing, shortness of breath, or a cough. This can help diagnose problems like asthma and COPD, or can be done to check lung function before a surgery. You may also have spirometry done if you are being treated for a chronic lung disease, such as COPD, asthma, or pulmonary fibrosis, to determine if your disease is improving or worsening and whether your medications or inhalers are working properly. Spirometry can be done in the doctor’s office or in a special pulmonary function testing lab.

What to Expect?

On the day of the test, you may be asked to not use certain inhalers or medications. Wear loose clothing and avoid big meals before testing.
These tests are not painful. They are performed by a pulmonary function technician. The tests are repeated several times to make sure the results are accurate. When performing the test, keep the following in mind:

You should take your daily medications prior to testing unless told otherwise.
Do not smoke for at least six hours prior to testing.
If you are taking a short-acting inhaler that is used only as needed, do not use for six to eight hours prior to testing, if possible.
Your doctor may give you other instructions regarding medications.
During the test, you will be sitting upright. A clip is placed on your nose and you will be given a plastic mouthpiece connected to the spirometry machine. You will place your lips tightly around the mouthpiece and be asked to take in as big and deep a breath as possible and then blow out as hard and fast as you can. This maximal effort is very important, and testing will be repeated at least three times to get the best results.

The technician may give you a medicine to help open your airways and then repeat the test to see if your breathing improves with the medicine. The testing takes about 30 to 45 minutes.