An International Randomized Multicenter Comparison of Nasal Potential Difference Techniques

Abstract

The agar nasal catheter approach demonstrates superior reliability compared with the perfusion nasal catheter method for measurement of NPD. This nonperfusion catheter method should be considered for adoption as a standardized protocol to monitor CFTR activity in clinical trials.

Acquired Cystic Fibrosis Transmembrane Conductance Regulator Dysfunction in the Lower Airways in COPD

“…The mean difference in D chloride-free isoproterenol between the two measurements was 1.43 Ϯ 3.59 mV, which compared favorably to prior NPD studies. 20,23 LAPD also revealed abnormalities in estimates of sodium transport, including reduced baseline ( Fig 3B ) and amiloridesensitive ( Fig 3C ) potential differences in healthy smokers and COPD smokers compared with healthy nonsmokers.…”

“…The severity of bronchitic symptoms was assessed with the Breathlessness, Cough, and Sputum Scale (BCSS). 19 NPD Measurements: NPD studies were performed according to the description by Solomon et al 20 with Electronic Data Capture (ADInstruments), KCl calomel electrodes (Thermo Fisher Scientifi c Inc), and 3% agar nasal catheter and reference bridges. 15,21 Lower Airway Potential Difference Measurements: During bronchoscopy under conscious sedation with limited topical analgesia (1% lidocaine to the vocal cords and right mainstem bronchus), lower airway potential difference (LAPD) measurements were performed to quantify CFTR activity in the lower airway ( Fig 1 ).…”

Functional Evaluation of Cystic Fibrosis Transmembrane Conductance Regulator

“…Recent standardization has demonstrated an improved performance of this diagnostic modality for CF [ 87 ]. The standardization process includes the aforementioned improvements in the method including using an electronic data capture system (AD Instruments, Colorado Springs, CO), KCl calomel electrodes (Fisher Scientifi c, Pittsburgh, PA), and agar two-lumen human interface; this standard operating procedure is maintained by the CFF Therapeutics Development Network Center for CFTR Detection National Resource Center.…”

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

“…Since then, various modifications to the original method have been published and efforts have been made recently to standardize NPD in American and European CF working groups [8][9][10][11][12]20]. Solomon et al showed that non-perfusion catheters are preferred to the perfusion catheters, with a better stability of the tracings and an enhanced CFTR-dependent chloride transport [13]. Currently, two different non-perfusion NPD methods are considered acceptable.…”

“…In the US only the first method is used, whereas both methods are used in European CF centres. Solomon et al compared Abr and Ndl only in a small number of healthy subjects, but not in CF and not in a blinded fashion [13]. No difference was demonstrated between the techniques.…”