Medicine General d0078850 All of the following explains diagnosis of Asthma except A After administering bronchodilator FEV1 increase to > 200mL within 15 minutes B PEFR shows diurnal variation of >20% C >12% reversibility in FEV1 on administering bronchodilator D Diffusion Lung Capacity for carbon monoxide is decreased High-Yield Explanation DLCO is normal in Asthma.