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

Area of Science:

• Medical Diagnostics
• Respiratory Medicine
• Clinical Physiology

Background:

• European and US protocols accept two nasal potential difference (NPD) measurement methods: subcutaneous agar-filled needle (Ndl) and dermal abrasion (Abr).
• These methods have not been formally compared for their discriminative value and subject preference in cystic fibrosis (CF) diagnosis.
• CF is a genetic disorder affecting lungs and other organs.

Purpose of the Study:

• To compare the discriminative value of Ndl and Abr methods for diagnosing CF.
• To assess subject preference between the two NPD measurement techniques.
• To evaluate the reliability of NPD measurements in CF patients and healthy volunteers (HV).

Main Methods:

• Twelve classic CF patients and 17 HV underwent both Ndl and Abr NPD methods.
• Measurements were performed by a single operator in a randomized order.
• Subject preference was assessed via questionnaire, and tracings were semi-blinded and categorized.

Main Results:

• A total of 110 tracings (56 Ndl, 54 Abr) were analyzed, with 42 classified as CF and 68 as non-CF.
• Both methods demonstrated good correlation and similar discriminative value.
• No significant difference in subject preference was reported between the Ndl and Abr methods.

Conclusions:

• Both NPD measurement methods (Ndl and Abr) exhibit comparable discriminative value and subject preference for diagnosing CF in comparison with HV.
• The choice of NPD method for CF diagnosis can be based on operator preference.
• NPD measurements are a valuable tool in CF diagnostics.