Nasal potential difference in non-classic cystic fibrosis-long term follow up.
BACKGROUND
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.
Jaron
Ranit
R
Cystic Fibrosis Center, Hadassah University Hospital, Jerusalem, Israel.
Yaakov
Yasmin
Y
Rivlin
Joseph
J
Blau
Hannah
H
Bentur
Lea
L
Yahav
Yakov
Y
Kerem
Eitan
E
Bibi
Haim
H
Picard
Elie
E
Wilschanski
Michael
M
D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000503:physiopathology*; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008564:Membrane Potentials; D009297:Nasal Mucosa / Q000503:physiopathology*; D015203:Reproducibility of Results