What is lung diffusion capacity?

Lung Diffusion Capacity

Lung diffusion capacity is a simple, painless test to determine how well oxygen moves or diffuses into your bloodstream from your lungs. Doctors use lung diffusion capacity to diagnose and monitor conditions that affect the lungs’ ability to transfer oxygen into the bloodstream. Conditions include emphysema, cystic fibrosis, and pulmonary embolism (blood clot in the lungs).

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

Other procedures that may be performed

Lung diffusion capacity is a type of pulmonary or lung function test. Your doctor will may perform one or more other pulmonary function tests to diagnose and monitor your respiratory disease, disorder or condition. Other 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. Lung diffusion capacity may 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.

  • Peak expiratory flow to measure the speed of exhaling and lung constriction. People with asthma use this test routinely to monitor their asthma control.

  • Pulse oximetry to measure oxygen levels in the blood

  • Spirometry to measure the rate and amount of air that you inhale and exhale

Medical Reviewers: Daphne E. Hemmings, MD, MPH Last Review Date: Jul 14, 2013

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Medical References

  1. 1.0 What is a PFT Test? Lung Diffusing Capacity. Morgan Scientific, Inc.
  2. Diffusing capacity for carbon monoxide. Wolters Kluwer Health.
  3. Lung Diffusing Capacity. Karger.
  4. Lung Diffusion Capacity Testing (DLCO). National Jewish Health.
  5. Pulmonary Function Testing: Diffusing Capacity. Cleveland Clinic Center for Continuing Education.

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