A full lung function test is a diagnostic test used by doctors to measure how well a patient’s lungs are working. Usually, doctors will order this test to be done in order to:

  • Diagnose certain types of lung disease (such as asthma, bronchitis, and emphysema)
  • Assess the severity of lung disease
  • Assess the effect of medication
  • Measure the progress of treatment
  • Test lung function before a surgery
  • Investigate the cause of shortness of breath

The lung function test is divided into three types of tests:

  • Spirometry, with or without bronchodilator
  • Diffusion Lung Carbon Dioxide (DLCO)
  • Body plethysmography (lung volume)

Spirometry is the first and most commonly done lung function test. It measures how much and how quickly patient can move air from the lungs. The test will require patient to breathe into a mouthpiece attached to a recording device (spirometer).

DLCO is known as a gas diffusion test. The test measures the amount of oxygen and other gases that cross into the lung’s air sacs to evaluate how well gases are absorbed into the body from the lungs.

Body plethysmography may be used to measure total lung capacity (maximum volume of air that the lungs can hold) or the residual volume of air that remains in the lung after patient exhales completely.


Services & Procedures offered

Lung function tests are done by specially trained respiratory therapists, or technicians. Testing may take roughly 5 to 30 minutes, depending on how many tests are done. Lung function tests present little to no risks to a healthy person. However, if you have any concerns, or serious heart and lung problems, consult with your doctor regarding the risks you may face.Before the test:

  • Do not eat a heavy meal and avoid caffeine
  • Avoid vigorous exercise
  • Do not smoke for at least 4 – 6 hours

You may get specific instructions if you need to stop using bronchodilators or inhaler medications. You may have to breathe in medication before or during the test. Do wear loose clothes that will not restrict your breathing.Please inform your doctor if you have experienced any chest pains or heart attacks recently. Also, let your doctor know if you are taking medication for lung complications, have any allergies or had recent surgeries so he can determine which test would best suit your needs.