Spyridon Fortis1, Edward O Corazalla2, Hyun J Kim3. 1. Pulmonary and Critical Care Division, Department of Medicine, University of Iowa, United States. Electronic address: spyridon-fortis@uiowa.edu. 2. Pulmonary Function Test Laboratory, University of Minnesota Medical Center, United States. Electronic address: ecorazalla@umphysicians.umn.edu. 3. Pulmonary Function Test Laboratory, University of Minnesota Medical Center, United States; Pulmonary and Critical Care Division, Department of Medicine, University of Minnesota, United States. Electronic address: kimxx015@umn.edu.