Physician perspectives on the most useful methods for monitoring α1-antitrypsin deficiency in the clinical trial setting versus clinical practice. Physician perspectives on the most useful methods for monitoring α1-antitrypsin deficiency in the clinical trial setting versus clinical practice. FEV1: forced expiratory volume in 1 s; DLCO: diffusing capacity of the lung for carbon monoxide; QCT: quantitative computed tomography; QoL: quality of life. Ildikó Horváth et al. ERJ Open Res 2019;5:00171-2018 ©2019 by European Respiratory Society