Nasal Potential Difference (NPD) for the Diagnosis of Cystic Fibrosis

The purpose of this research study is to provide a novel method for the diagnosis of Cystic Fibrosis (CF). This protocol is designed to test the ability of the cells to regulate the movement of salt and water in people with features of CF in whom the diagnosis is not entirely clear. We will be studying these cells in the nose, by a technique called nasal transepithelial potential difference (NPD).