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Lung Function Tests


Lung function tests check to see how well your lungs work. The tests can find lung problems, measure how serious they are, and check to see how well treatment for a lung disease is working.

The tests look at:

  • How much air your lungs can hold.
  • How quickly you can move air in and out of your lungs.
  • How well your lungs put oxygen into and remove carbon dioxide from your blood.

Types of lung function tests include:

  • Spirometry.
  • Gas diffusion.
  • Body plethysmography.
  • Inhalation challenge test.
  • Exercise stress test.

You may also hear the tests called pulmonary function tests, or PFTs.

Lung function results are measured directly in some tests and are calculated in others.

No single test can check for all of the lung function values, so more than one type of test may be done. Some tests may be repeated after you inhale medicine that enlarges your airways (bronchodilator).

Why are lung function tests done?

Doctors use lung function tests to find the cause of breathing problems and diagnose lung diseases like asthma or emphysema. You may have lung function tests before you have surgery. Or your doctor may use lung function tests to find out how well treatment for a lung problem is working.