Lung function tests are used to address breathing problems (like shortness of breath) and screen for conditions such as asthma, lung tissue scarring, sarcoidosis and COPD (chronic obstructive pulmonary disease).

Lung function tests for elderly seniors also are used to see how well treatments for breathing problems, such as asthma medicines, are working. The tests may be used to determine whether a condition, such lung tissue scarring, is getting worse.

Lung function tests measure:

  • How much air a person can take into their lungs. This amount is compared to that of other people who are the same age, height and sex.
  • How much air a person can blow out of their lungs and how fast they can do it.
  • How well a person's lungs deliver oxygen to the blood.
  • How strong a person's breathing muscles are.

Breathing Tests

The most commonly used breathing tests include:

Spirometry. This test measures how much air one can breathe in and out and how quickly.

Peak flow meter. This meter is a small, hand-held device that is sometimes used by people who have asthma. The meter helps track their breathing.

Lung volume measurement. This test, in addition to spirometry, measures how much air is left in the lungs after one breathes out completely.

Lung diffusing capacity. This test measures how well oxygen passes from the lungs to the bloodstream. These tests may not show what's causing breathing problems. Other tests, such as a cardiopulmonary exercise test, also may be done. This test measures how well the lungs and heart work while a person exercises on a treadmill or stationary bicycle.


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Blood oxygen tests. Pulse oximetry and arterial blood gas are two tests used to measure the oxygen level in the blood. Pulse oximetry measures blood oxygen levels using a special light.

During an arterial blood gas test, the doctor inserts a small needle into an artery, usually in the wrist, and takes a sample of blood. The oxygen level of the blood sample is then checked.

Lung function tests are usually painless and rarely cause side effects.

Source: The National Heart, Lung, and Blood Institute; https://www.nhlbi.nih.gov/