A semi-blinded study comparing 2 methods of measuring nasal potential difference: Subcutaneous needle versus dermal abrasion

J Cyst Fibros. 2016 Jan;15(1):60-6. doi: 10.1016/j.jcf.2015.06.007. Epub 2015 Jul 16.

Abstract

Background: According to European and US protocols, two nasal potential difference (NPD) measurement methods are considered acceptable, although they have not been formally compared: subcutaneous agar-filled needle with calomel (Ndl) and dermal abrasion with conducting cream and Ag/AgCl electrodes (Abr). We compared both in CF and healthy volunteers (HV), assessing their discriminative value and subject's preference.

Methods: Twelve classic CF and 17 HV underwent both NPD methods, performed by one operator in random order. A written questionnaire, assessing preference, was completed after each test. Tracings were coded, scored in a semi-blinded fashion and categorised as CF/non-CF.

Results: 110 tracings (56 Ndl/54 Abr) were collected: 42/110 scored CF and 68/110 non-CF, showing a good correlation. No significant preference for either method was reported.

Conclusion: Both NPD methods are similar in terms of discriminative value and subject's preference, comparing classical CF and HV. For diagnosing CF, the operator's preferred NPD-method may be used.

Keywords: CF diagnosis; dermal abrasion method; nasal potential difference measurements; needle method.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Chlorides* / analysis
  • Chlorides* / metabolism
  • Cystic Fibrosis* / diagnosis
  • Cystic Fibrosis* / metabolism
  • Cystic Fibrosis* / physiopathology
  • Electrodiagnosis / instrumentation
  • Electrodiagnosis / methods
  • Female
  • Humans
  • Male
  • Membrane Potentials
  • Nasal Mucosa / physiopathology*
  • Patient Preference
  • Reproducibility of Results
  • Sweat / metabolism*

Substances

  • Chlorides