[Measurement of nasal transepithelial potential difference: a diagnostic test for cystic fibrosis]

Measurement of nasal transepithelial potential difference allows the exploration of transepithelial ionic transports in vivo. Cystic fibrosis is an interesting indication of this test. Indeed, this disease is characterized by a chloride and water secretion deficit across respiratory epithelium. We have measured nasal potential in 8 healthy volunteers. Measurements were repeated 3 times a day, during 3 days for each subject. The reproducibility of the data was analysed with factorial variance model. The mean nasal potential in the healthy volunteers group and in 10 patients with cystic fibrosis was compared. In the cystic fibrosis group, the nasal potential was measured 3 times with a 2 mn-interval between the measurements. No significant variation of the nasal potential values was found from day to day or in the same day from one measurement to another. Mean value was -19 +/- 3.5 mv in normal subjects and -42.6 +/- 5.1 mv in cystic fibrosis patients. We conclude that nasal potential measurement is an easy and reproducible test that might be a complementary tool routinely used along with the classical tests in the diagnosis of cystic fibrosis.