Nasal potential difference (NPD) measurement is an electrophysiological test that assesses cystic fibrosis transmembrane conductance regulator (CFTR) activity and is a recognized diagnostic tool in CF. The aim of this study is to assess in the long term the role of NPD in patients whose diagnosis is questionable.Methods:
We performed follow up study on 70 patients with questionable CF (QCF) who were divided previously into two groups according to their NPD results: patients who likely have CF (QCF-CF) (n=24), and those who likely do not have CF (QCF-non-CF) (n=46).Results:
Sixty out of 70 patients were available for study. Sixteen patients in the QCF-CF group were being followed up at CF Centers as opposed to 1 in the QCF-non-CF group (P<0.01). Seven patients from the QCF-CF group developed sinusitis during the follow up years compared to none from the QCF-non-CF group. During the years of the follow up, 17 QCF-non-CF patients were diagnosed with other medical conditions that could explain their previous symptoms. On repeated NPD measurement in the QCF-CF group, the results were similar to the original test.Conclusions:
This study supports the diagnostic role of NPD measurement. Larger cohort studies are required for confirmation. Pediatr Pulmonol. 2008; 43:545-549. © 2008 Wiley-Liss, Inc.