Spirometry is the most common pulmonary function test measured. It consists of a breathing test done by blowing into a tube while sitting in a chair. Spirometry measures how much air you can breathe in and out, as well as how fast you can breathe in and out. You may be asked to breathe quickly, forcefully, or slowly. Often the test is repeated three times or more to be sure the test results are consistent and reliable.
Your healthcare provider may order a bronchodilator to be given. This medicine is inhaled to open up your airways. Spirometry is then done before and after the bronchodilator to see if the medication will help. If your airways open up with the medication, this helps your healthcare provider determine what kind and how much airway disease you have and whether medication will help you.