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
Answer is D. DLCO is normal in Asthma.