Spirometry is used to diagnose and monitor the progress of COPD. According to the National Lung Health Education Program, all persons aged 45 or older who currently smoke or have quit smoking should have a spirometry test.
The test is done in the doctor’s office and takes only a few minutes to complete. You will be asked to take a deep breath in and then blow out all the air in your lungs as hard and fast as you can for at least six seconds.
After the test is completed, the doctor will look at 2 important numbers:
FEV1—the amount of air that is blown out in the first second of exhalation
FEV1/FEV6—a ratio of the time it takes you to blow out one second to the amount of air that you can blow out in six seconds. This number (written as a percent) gives the doctor important information needed to make the diagnosis of COPD.