What are lung function tests?

Lung function tests are used to find out how well your lungs are working. They most often include spirometry, where you breathe out quickly and forcefully through a tube connected to a machine. This machine then measures how much air your lungs can hold and how quickly air moves in and out of your lungs. A lung volume test is also included, which measures the amount of air your lungs can hold at different times, and lung diffusion tests, which show how well your body moves oxygen and carbon dioxide between your lungs and your blood.