What is spirometry?

Spirometry is a type of pulmonary function test, or a lung function test, that measures the flow of air through your lungs. It also estimates the amount of air in your lungs. The test is performed using a machine called a spirometer. It measures the amount of air you breathe and how fast you can blow air out of your lungs. Spirometry is a safe and commonly ordered test.

Why is spirometry done?

Spirometry tests determine if lungs are functioning at expected levels. It helps to diagnose lung and airway diseases. For example, the test can detect chronic obstructive pulmonary disease (COPD) before symptoms develop. The test can also check for pulmonary fibrosis, or scarring of the lung tissue.

Other reasons why spirometry is done:

  • To determine lung capacity
  • To measure the changes over time of chronic diseases on lung function
  • To identify early changes in lung function and in some cases to help guide treatment
  • To detect narrowing in the airways
  • To decide how likely it is that inhaled medicines may help with symptoms
  • To show whether exposure to substances has altered lung function
  • To estimate your risk of respiratory complications before undergoing surgery

Last reviewed by a Cleveland Clinic medical professional on 07/12/2018.


  • National Institutes of Health. COPD: Diagnosis. Accessed 7/17/2018.
  • Ranu H, Wilde M, Madden B. Pulmonary function tests. Ulster Med J. 2011;80(2):84-90. Accessed 7/17/2018.
  • Fahy B, Sockrider M, Lareau S. Pulmonary function tests. Am J Respir Crit Care Med. 2014;189:17-18.


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