<prompt> Diffusion capacity for carbon monoxide is decreased in all of the following exceptChronic bronchitisEmphysemaInterstitial lung diseasePulmonary embolism  <response>: Diffusion capacity for carbon monoxide DLCO is usually nirmln in chronic bronchitis and other obstructive lung disease with the exception of empyseemp where it is decreased. Ref Harrison 19th edition pg 1710 