<prompt> Which of the following statement regarding COPD is true?Decrease FEV1Increased RVDiffusion capacity is decreasedAll of the above  <response>: Spirometry findings in COPD includes reduced FEV1 and a reduced FEV1 FVC ratio. Diffusion capacity for carbon monoxide reflects the ability of lung to transfer gas across alveolarcapillary interface. Diffusion capacity is low in patients with emphysema and infiltrative lung diseases. It is increased in patients with pulmonary hemorrhage, congestive hea failure and asthma. Reference: Current Medical Diagnosis and Treatment 2013, chapter 9. 