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CompletedNCT00589745Updated Jan 29, 2020

Nasal Potential Difference (NPD) for the Diagnosis of Cystic Fibrosis

An interventional study of Nasal potential difference measurement in Cystic Fibrosis, sponsored by Children's Hospital of Philadelphia. Completed at 1 site in United States. Per ClinicalTrials.gov, last updated 2020-01-29.

Sponsored by Children's Hospital of Philadelphia · Not applicable, Interventional, and Diagnostic

Phase
Not applicable
Study type
Interventional
Enrollment
27
Allocation
Not applicable
Sex
All
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Study summary

The purpose of this research study is to provide a novel method for the diagnosis of Cystic Fibrosis (CF). This protocol is designed to test the ability of the cells to regulate the movement of salt and water in people with features of CF in whom the diagnosis is not entirely clear. We will be studying these cells in the nose, by a technique called nasal transepithelial potential difference (NPD).

Read the detailed description

Cystic Fibrosis (CF) is an autosomal recessive systemic disorder of exocrine glands and secretory epithelia. The disease results from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene which cause a variety of abnormalities. CFTR is absent or dysfunctional in cystic fibrosis. Most of the defects in CFTR result in abnormal chloride ion transport and abnormally viscous mucus. Nasal epithelial CFTR function will be assessed by the NPD procedure.

NPD measurements are useful as a diagnostic tool in individuals with borderline or normal sweat chlorides, one or no identified CFTR mutations, and a clinical history suggestive of CF. The NPD has become the gold standard for detection and quantification of CFTR function in the airways. The assay has also served as an important endpoint since 1981. It has been used extensively and is standardized to assess the ability of new therapeutics in studies designed to replace, repair or restore defective ion transport in CF patients.

The assay basically involves dripping small amounts of the test solutions into the anterior nostril in order to measure uptake or secretion of sodium and chloride. There are five solutions required for the NPD measurement:

  • Solution #1: Buffered Ringers
  • Solution #2: Solution #1+Amiloride
  • Solution #3: Buffered Zero Chloride Solution + Amiloride
  • Solution #4: Solution #3 + Isoproterenol
  • Solution #5: Solution #4 + Adenosine 5'-Triphosphate-Disodium salt (ATP)

The Cystic Fibrosis Therapeutics Development Network (TDN) is a formal affiliation of CF Research Centers in the US. Two Standard Operating Procedures have been developed by the TDN for the NPD procedure and qualification of those performing the measurement.

Procedure Details:

Briefly, a series of stopcocks is configured to allow perfusion of the above solutions through the port at the tip of an exploring catheter (PE50 tubing. All test solutions are perfused at a rate of 5.0 cc per minute. In each nostril, the PD readings in Ringer's at 0.5, 1.0, 1.5, 2, and 3 cm (lumen negative) are averaged and taken as the average 'baseline' PD. The catheter tip is then placed at the most negative PD site and maintained for superperfusion measurements with a small piece of tape applied to the nasal tip (to hold the catheter for the duration of the protocol). All solutions are warmed to 37˚C prior to contact with the nasal mucosa.

For each perfusion condition, a steady-state recording is obtained. The recording lasts at least one minute (for Solution #1) and for three minutes (for Solutions #2, 3, and 4) prior to proceeding to the next solution within the sequence. Solution #5 is perfused for a minimum of one minute, and confirms retention of ATP-activated Clˉ secretion in both CF and non-CF individuals. Several readings are obtained for data analysis, and then all nasal P.D. tracings are scored by investigators.

02

Conditions studied

  • Cystic Fibrosis

Keywords

  • Diagnosis
03

In context

Cystic Fibrosis

1,581 studies on the registry are indexed under Cystic Fibrosis; 190 are open to participants now.

This study's enrollment of 27 is below the median of 36 across 1,034 interventional studies indexed under Cystic Fibrosis.

Browse Cystic Fibrosis studies →

Lead sponsor

Children's Hospital of Philadelphia is the lead sponsor of 480 studies on the registry; 85 are open to participants now.

Of its 28 completed or terminated interventional studies of FDA-regulated products, 22 (79%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
Child (0–17), Adult (18–64), Older adult (65+)
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • All ethnic groups accepted
  • Individuals with borderline or normal sweat chloride, one or no identified CFTR mutations and a clinical history suggestive of CF.
  • Children less than 6-8 years of age may be unable to cooperate (hold still) for the procedure, or be frightened by the procedure. Sedation may be necessary for performance of the procedure on a young child

Exclusion criteria

Exclusion Criteria:

  • n/a
05

Study design

Phase
Not applicable
Primary purpose
Diagnostic
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
27 participants (actual)

Study arms

  • Other
    Subjects being evaluated for CF

    Subjects will be referred from physicians who are clinically concerned about the possibility of Cystic Fibrosis. Nasal potential difference measurement will be obtained to potentially help aid in diagnosis.

    Other: Nasal potential difference measurement

Interventions

  • OtherNasal potential difference measurement

    Nasal potential difference measurement involves dripping small amounts of 5 test solutions into the anterior nostril. This is designed to test the ability of the cells to regulate the movement of salt and water in people with features of CF in whom the diagnosis is not entirely clear.

    Also known as: NPD

06

What researchers measure

Primary outcomes

  1. The basis of analysis will be the NPD response patterns, which will be interpreted and classified by the PI, as consistent or inconsistent with the diagnosis of CF based on comparison with published standards.

    Time frame: Every visit

07

Study locations

1 site
  • Children's Hospital of Philadelphia
    Philadelphia, Pennsylvania 19104, United States
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Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jan 29, 2020, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT00589745
Lead sponsor
Children's Hospital of Philadelphia
Responsible party
Sponsor
First posted
Jan 10, 2008
Start date
Sep 2003
Primary completion
Dec 18, 2019
Completion
Dec 18, 2019
Last update
Jan 29, 2020

Study contacts

Ronald Rubenstein, M.D., PhD.
principal investigator · Children's Hospital of Philadelphia

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Jan 2020. You cannot join it, but the record below documents what was studied.

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