How abnormal is the normal? Clinical characteristics of CF patients with normal FEV.

Background: Normal values (>80%) of Forced Expiratory Volume in one second (FEV ) in patients with cystic fibrosis (CF) may lead to the interpretation that there is no lung disease. This study is a comprehensive analysis of lung involvement in CF patients having normal FEV .

Methods: Patients were recruited from two CF centers: Hadassah Medical Center, Jerusalem and Vall d' Hebron Hospital, Barcelona.