Pulmonary function tests (PFT) measure how efficiently an individual’s lungs perform their essential tasks. Several separate techniques are used to determine the amount of air the lungs can hold, how well the lungs move air into and out of the body and how effectively the lungs exchange oxygen and carbon dioxide.

There are three primary phases of pulmonary function testing:

• Spirometry
• Lung volume measurement
• Diffusion capacity measurement

However, there are variations on these tests that also can provide physicians with insights into lung disorders. All of these tests provide measures of various lung functions, including tidal volume, carbon monoxide response, total lung capacity and many more. With this information, physicians can accurately diagnose both the nature of a lung disorder and its severity.

There are also a number of at–home tests, such as peak flow meters, that patients can use themselves to monitor lung function.