BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuLung diffusion testingDiffusing capacity; DLCO testLung diffusion testing measures how well the lungs exchange gases. This is an important part of lung testing, because the major function of the lungs is to allow oxygen to diffuse or pass into the blood from the lungs, and to allow carbon dioxide to diffuse from the blood into the lungs.Lung testingPulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning.ImageRead Article Now Book Mark Article How the Test is Performed You breathe in (inhale) air containing a very small amount of carbon monoxide and a tracer gas, such as methane or helium. You hold your breath for 10 seconds, then rapidly blow it out (exhale). The exhaled gas is tested to determine how much of the tracer gas was absorbed during the breath.Carbon monoxideCarbon monoxide is an odorless gas that causes thousands of deaths each year in North America. Breathing in carbon monoxide is very dangerous. It i...Read Article Now Book Mark Article How to Prepare for the Test Before taking this test:Do not eat a heavy meal before the test. Do not smoke for at least 4 to 6 hours before the test. If you use a bronchodilator or other inhaled medicines, ask your health care provider whether or not you can use them before the test. How the Test will Feel The mouthpiece fits tightly around your mouth. Clips are put on your nose. Why the Test is Performed The test is used to diagnose certain lung diseases, and to monitor the status of people with established lung disease. Repeatedly measuring the diffusing capacity can help determine whether the disease is improving or getting worse. Normal Results Normal test results depend on a person's: Age Sex Height Hemoglobin (the protein in red blood cells that carries oxygen) level What Abnormal Results Mean Abnormal results mean that gases do not move normally across the lung tissues into the blood vessels of the lung. This may be due to lung diseases such as:COPD COPDChronic obstructive pulmonary disease (COPD) is a common lung disease. Having COPD makes it hard to breathe. There are two main forms of COPD:Chroni...ImageRead Article Now Book Mark Article Interstitial fibrosis Interstitial fibrosisInterstitial lung disease (ILD) is a group of lung disorders in which the lung tissues become inflamed and then damaged.ImageRead Article Now Book Mark Article Pulmonary embolism Pulmonary embolismA pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.ImageRead Article Now Book Mark Article Pulmonary hypertension Pulmonary hypertensionPulmonary hypertension is high blood pressure in the pulmonary arteries of the lungs. It makes the right side of the heart work harder than normal....ImageRead Article Now Book Mark Article Sarcoidosis SarcoidosisSarcoidosis is a disease in which inflammation occurs in the lymph nodes, lungs, liver, eyes, skin, and/or other tissues.ImageRead Article Now Book Mark Article Bleeding in the lung Asthma AsthmaAsthma is a chronic disease that causes the airways of the lungs to swell and narrow. It leads to breathing difficulty such as wheezing, shortness o...ImageRead Article Now Book Mark Article Reduced lung volume (capacity) Risks There are no significant risks. Considerations Other pulmonary function tests may be done together with this test.Pulmonary function testsPulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning.ImageRead Article Now Book Mark Article Open ReferencesReferencesBhakta NR, Kaminsky DA. Pulmonary function testing: Physiologic and technical principles. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 31.Scanlon PD, Niven AS. Respiratory testing and function. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 73.AllVideoImagesTogLung diffusion testing - illustration Lung diffusion testing measures how well oxygen passes from the air sacs in the lungs into the blood.Lung diffusion testingillustrationLung diffusion testing - illustration Lung diffusion testing measures how well oxygen passes from the air sacs in the lungs into the blood.Lung diffusion testingillustrationA Closer Look Chronic obstructive pulmonary disease - InDepth(In-Depth) Tests for Lung diffusion testing Lung diffusion testingPulmonary function testsRelated Information Lung disease(Condition)Interstitial lung disease(Condition)Sarcoidosis(Condition)Asbestosis(Condition) Review Date: 11/25/2023 Reviewed By: Denis Hadjiliadis, MD, MHS, Paul F. Harron Jr. Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David C. 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Lung diffusion testingDiffusing capacity; DLCO testLung diffusion testing measures how well the lungs exchange gases. This is an important part of lung testing, because the major function of the lungs is to allow oxygen to diffuse or pass into the blood from the lungs, and to allow carbon dioxide to diffuse from the blood into the lungs.Lung testingPulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning.ImageRead Article Now Book Mark Article How the Test is Performed You breathe in (inhale) air containing a very small amount of carbon monoxide and a tracer gas, such as methane or helium. You hold your breath for 10 seconds, then rapidly blow it out (exhale). The exhaled gas is tested to determine how much of the tracer gas was absorbed during the breath.Carbon monoxideCarbon monoxide is an odorless gas that causes thousands of deaths each year in North America. Breathing in carbon monoxide is very dangerous. It i...Read Article Now Book Mark Article How to Prepare for the Test Before taking this test:Do not eat a heavy meal before the test. Do not smoke for at least 4 to 6 hours before the test. If you use a bronchodilator or other inhaled medicines, ask your health care provider whether or not you can use them before the test. How the Test will Feel The mouthpiece fits tightly around your mouth. Clips are put on your nose. Why the Test is Performed The test is used to diagnose certain lung diseases, and to monitor the status of people with established lung disease. Repeatedly measuring the diffusing capacity can help determine whether the disease is improving or getting worse. Normal Results Normal test results depend on a person's: Age Sex Height Hemoglobin (the protein in red blood cells that carries oxygen) level What Abnormal Results Mean Abnormal results mean that gases do not move normally across the lung tissues into the blood vessels of the lung. This may be due to lung diseases such as:COPD COPDChronic obstructive pulmonary disease (COPD) is a common lung disease. Having COPD makes it hard to breathe. There are two main forms of COPD:Chroni...ImageRead Article Now Book Mark Article Interstitial fibrosis Interstitial fibrosisInterstitial lung disease (ILD) is a group of lung disorders in which the lung tissues become inflamed and then damaged.ImageRead Article Now Book Mark Article Pulmonary embolism Pulmonary embolismA pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.ImageRead Article Now Book Mark Article Pulmonary hypertension Pulmonary hypertensionPulmonary hypertension is high blood pressure in the pulmonary arteries of the lungs. It makes the right side of the heart work harder than normal....ImageRead Article Now Book Mark Article Sarcoidosis SarcoidosisSarcoidosis is a disease in which inflammation occurs in the lymph nodes, lungs, liver, eyes, skin, and/or other tissues.ImageRead Article Now Book Mark Article Bleeding in the lung Asthma AsthmaAsthma is a chronic disease that causes the airways of the lungs to swell and narrow. It leads to breathing difficulty such as wheezing, shortness o...ImageRead Article Now Book Mark Article Reduced lung volume (capacity) Risks There are no significant risks. Considerations Other pulmonary function tests may be done together with this test.Pulmonary function testsPulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning.ImageRead Article Now Book Mark Article Open ReferencesReferencesBhakta NR, Kaminsky DA. Pulmonary function testing: Physiologic and technical principles. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 31.Scanlon PD, Niven AS. Respiratory testing and function. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 73.
