Lung diffusing capacity test

The diffusion of gas from alveolar air into pulmonary circulation is measured using different gases (such as helium, carbon monoxide).

Typically, lung diffusing capacity decreases with the reduction of diffusion area, for example, in the case of emphysema concomitant with chronic obstructive pulmonary disease (COPD).

The test is used for diagnosing diffuse processes or processes extensively damaging alveolar walls or alveolar circulation, for identifying interstitial lung diseases and alveolitis, etc.