Lung diffusion testing

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Lung diffusion testing

Definition:

Lung diffusion testing is used to determine how well oxygen passes from the air sacs of the lungs into the blood. The test measures the "diffusing capacity of the lung for carbon monoxide" or DLCO.

Alternative Names:
Diffusing capacity; DLCO test
How the test is performed:

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You breath in (inhale) some gas containing a very small quantity of carbon monoxide, hold your breath for 10 seconds, then rapidly blow it out (exhale). The single exhaled gas is analyzed to determine how much carbon monoxide was absorbed during the breath.

How to prepare for the test:

Do not eat a heavy meal before the test. Do not smoke for at least 4 - 6 hours prior to the test. If you use a bronchodilator or inhaler medications, ask your health care provider whether or not you can use them before the test.

How the test will feel:

The mouth piece fits tightly around your mouth. Clips are put on the nose.

Why the test is performed:

The test is used to diagnose the presence and extent of certain lung diseases. It may also be used to see how gases move the lungs into the bloodstream.

References:

Lamberto C, Nunes H, Le Toumelin P, Duperron F, Valeyre D, Clerici C. Membrane and capillary blood components of diffusion capacity of the lung for carbon monoxide in pulmonary sarcoidosis: relation to exercise gas exchange. Chest. 2004 Jun;125(6):2061-8.

Mohsenifar Z, Lee SM, Diaz P, et al. Single-Breath Diffusing Capacity of the Lung for Carbon Monoxide: A Predictor of PaO2, Maximum Work Rate, and Walking Distance in Patients With Emphysema. Chest 123: 1394-1400.