What is spirometry?

Spirometry is a simple, painless test that measures lung constriction and the speed of exhalation. Spirometry involves blowing into a mouthpiece while a spirometer records measurements on a graph. Doctors use spirometry to diagnose and manage diseases that affect breathing, such as asthma and COPD (chronic obstructive pulmonary disease). 

Spirometry is only one method of diagnosing and managing respiratory diseases. Discuss all your monitoring and testing options with your doctor to understand which options are right for you.

Other procedures that may be performed

Spirometry is a type of pulmonary or lung function test. Your doctor will likely recommend one or more other pulmonary function tests to diagnose and monitor your respiratory disease. Pulmonary function tests include:

  • Arterial blood gas test to measure oxygen and carbon dioxide levels and other factors in the blood 
  • Body plethysmography to determine how much air is present in your lungs when you take a deep breath and how much air is left in your lungs after you exhale as much as you can. Spirometry can be done at the same time as a body plethysmography using the same equipment.
  • Bronchoprovocation tests to measure lung function after exposure to factors that commonly trigger asthma. This includes a methacholine challenge test to help diagnose asthma.
  • Lung diffusion capacity to measure how well oxygen moves into your blood from your lungs
  • Peak expiratory flow to measure the speed of exhaling and lung constriction. People with asthma often use this test routinely to monitor their asthma control.
  • Pulse oximetry to measure oxygen levels in the blood

Why is spirometry used? 

Your doctor may recommend spirometry to diagnose and determine the severity of diseases that affect breathing. It is also used to determine how well treatments are working. Diseases include:

  • Asthma is a chronic lung disease marked by acute flare-ups of inflammation and swelling of the airways in the lungs.
  • Acute bronchitis is lung inflammation generally due to an infection of the bronchial tubes in the lungs.
  • Cardiac diseases include congestive heart failure, congenital (present at birth) heart disease, and pulmonary hypertension.
  • COPD (chronic obstructive pulmonary disease) includes emphysema and chronic bronchitis.
  • Cystic fibrosis is a genetic disorder that causes thick, sticky mucus buildup in the lungs and other organs.
  • Neuromuscular diseases include multiple sclerosis, myasthenia gravis, and Guillain-Barré syndrome.
  • Pneumonia is inflammation of the lungs, usually due to a viral or bacterial infection.
  • Pulmonary fibrosis is lung scarring due to the growth of excessive fibrous tissue in the lungs.

Your doctor may also use spirometry in the following situations: 

  • You are a current or former smoker. 
  • You are having surgery including abdominal, heart or lung surgery.
  • You have abnormal test results including abnormal arterial blood gases and chest X-ray.
  • You have symptoms of respiratory disease including chest tightness, cough, phlegm, wheezing, and shortness of breath.

Who performs spirometry?

A pulmonary function technologist, or specially trained respiratory therapist or nurse performs spirometry. A pulmonary function technologist is a healthcare provider who specializes in performing lung function tests to diagnose and treat lung diseases, including asthma, COPD (chronic obstructive pulmonary disease), and other breathing problems. 

The following types of doctors order and supervise spirometry testing:

  • Allergist-immunologists specialize in caring for people with allergies, asthma, and other diseases of the immune system.
  • Pediatric allergist-immunologists specialize in caring for children from infancy through adolescence with allergies, asthma, and other diseases of the immune system.
  • Pulmonologists specialize in the medical care of people with breathing problems and diseases and conditions of the lungs.
  • Pediatric pulmonologists specialize in the medical care of infants, children and adolescents with diseases and conditions of the lungs.