Repeatability and Diagnostic Value of Nasal Potential Difference in a Genetically Admixed Population

Area of Science:

• Medical Diagnostics
• Genetics
• Pulmonology

Background:

• Brazilian population's genetic diversity complicates cystic fibrosis (CF) diagnosis.
• Nasal potential difference (NPD) assesses CFTR and ENaC activity but is operator-dependent.
• Wilschanski and Sermet scores aim to improve NPD accuracy and interpretation.

Purpose of the Study:

• Evaluate the repeatability and diagnostic value of NPD parameters.
• Assess the utility of Wilschanski and Sermet scores in a Brazilian CF center.
• Determine the feasibility of NPD as a diagnostic tool in Brazil.

Main Methods:

• NPD performed on 78 subjects (healthy volunteers, non-CF, and CF patients).
• Analyzed maximal PD, amiloride response, total chloride response, and diagnostic scores.
• Used ANOVA and Scheffe tests for comparisons; Bland-Altman plots for repeatability.

Main Results:

• Significant differences in NPD parameters between CF patients and other groups (P = 0.000).
• No significant differences between healthy volunteers and non-CF patients (P > 0.05).
• NPD parameters and scores aligned with disease/non-disease status; repeatability confirmed.

Conclusions:

• Wilschanski and Sermet scores demonstrated concordance with CF/non-CF conditions.
• Repeatability data support the use of NPD in this Brazilian CF center.
• Further NPD testing in the Rio de Janeiro cohort is recommended for international validation.