Before the test, a technician places soft clips on your nose. This allows you to breathe only through a tube that's attached to the testing machine. The technician will tell you how to breathe into the tube. For example, you may be asked to breathe normally, slowly, or rapidly.
In this test, you take a deep breath and then exhale as fast and as hard as you can into the tube. With spirometry, your doctor may give you a medicine that helps open your airways. Your doctor will want to see whether it changes or improves the test results.
After the test, you can return to your normal activities and restart your medicines after lung function tests. Talk to your doctor about when you will get the test results.
Spirometry can show whether you have a blockage (obstruction) in your airways. This may be a sign of asthma, COPD (chronic obstructive pulmonary disease), or another obstructive lung condition. Spirometry may also show whether you have smaller than normal lungs (restriction). This may be a sign of heart failure, damage or scarring of the lung tissues, or another restrictive lung condition.