What are lung function tests?

Lung function tests (also known as pulmonary function tests) are used to look for the cause of breathing problems (like shortness of breath) and are also used to see how well treatments for breathing problems, such as asthma medicines, are working. They can be used to check for conditions such as asthma, lung tissue scarring, sarcoidosis, and COPD (chronic obstructive pulmonary disease). The tests may also be used to check whether a condition is getting worse.

Lung function tests measure:

  • How much air you can take into your lungs. This amount is compared to that of other people your own age, height, and sex;
  • How much air you blow out of your lungs and how fast you do it;
  • How well your lungs deliver oxygen to your blood; and
  • How strong your breathing muscles are.