Sweat Testing in Infants: Comparing Sweat Collection on Upper Vs Lower Limbs

Not Applicable

Not yet recruiting

• Conditions: Cystic Fibrosis (CF)

• Registration Number: NCT06902363
• Lead Sponsor: Universitair Ziekenhuis Brussel

Brief Summary

The goal of this study is to compare the rate of Quantity Not Sufficient (QNS) during sweat collection in infants under 6 months of age, using the Macroduct Advanced device for sweat testing. The main question it aims to answer is:

Does sweat collection from the thigh (lower limb) reduce the QNS rate compared to the forearm (upper limb) in infants? Do chloride concentration levels differ between sweat collected from the forearm and thigh in the same infants?

Detailed Description

This is a prospective, observational study aimed at evaluating the effectiveness of the Macroduct Advanced device for sweat testing in infants under 6 months of age. The primary goal is to compare the rate of Quantity Not Sufficient (QNS) between two sweat collection sites: the forearm (upper limb) and the thigh (lower limb). The study seeks to determine whether using the thigh as an alternative collection site can reduce the incidence of QNS, a common challenge in sweat testing in infants, where at least 15 microliters of sweat are required for an accurate result.

Study Objectives:

To assess if sweat collection from the thigh results in a lower QNS rate compared to the forearm in infants.

To compare the chloride concentration levels of sweat collected from both the forearm and thigh, in order to evaluate if the collection site affects the chloride measurements.

Study Design:

Participants will undergo sweat collection from both the forearm and thigh, within the same study session, using the Macroduct Advanced device.

The QNS rate will be recorded for each collection site. Chloride levels from the sweat samples will be measured for comparison between the two sites.

The study will involve healthy infants under 6 months of age, and data will be collected to evaluate the feasibility and effectiveness of using the thigh as a collection site for sweat testing.

Primary and Secondary Outcomes:

Primary Outcome: Reduction in the QNS rate when sweat is collected from the thigh compared to the forearm.

Secondary Outcome: Comparison of chloride concentration levels from the forearm and thigh to determine if there is a significant difference in chloride levels depending on the collection site.

This study will provide valuable insights into improving the accuracy and feasibility of sweat testing in infants, especially in cases where QNS is common and may require repeated tests. If successful, using the thigh as a collection site could enhance the overall success rate of sweat tests and reduce the need for retesting, improving clinical care for infants with conditions such as cystic fibrosis.

Study Timeline

• Status Verified: 2025-03
• Study First Submitted: 2025-03-24
• Study First Submitted QC: 2025-03-24
• Last Update Submitted: 2025-03-24
• Study Start: 2025-03-30
• Study First Posted: 2025-03-30
• Last Update Posted: 2025-03-30
• Primary Completion: 2025-08-01
• Study Completion: 2025-08-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• minimal 3,000 kg
• after a positive newborn screening (NBS) test. During this test, newborns are screened for rare diseases including CF. In case of a positive NBS test for CF, a sweat test is routinely performed to confirm or withdraw the diagnosis.
• after clinical assessment for CF, with ST as diagnostic step
• siblings of patients with CF in order to exclude CF
• CF patients who are willing to participate
• Healthy infants, born at the maternity unit of UZ Brussel, of which parents are willing to participate

Exclusion Criteria

• chromosome abnormalities
• metabolic abnormalities
• cardiopathies
• eczema
• important skin lesions on the limbs
• use of systemic corticosteroids
• critically ill patients (for example hemodynamically unstable)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Primary Outcome Measures

Name	Time	Method
Comparison of Sweat Collection Sites: Forearm vs. Thigh in Infants (Primary Outcome: QNS Rate)	Measurement of QNS rate will be taken at the time of sweat collection from both forearm and thigh, during each testing session. Data will be recorded in real-time, and analysis will occur immediately following the collection.	The primary objective of this study is to compare the rate of Quantity Not Sufficient (QNS) between sweat collected from the forearm (upper limb) and the thigh (lower limb) in infants under 6 months of age. Both sites will be tested on the same infant at the same time using the Macroduct Advanced device. The goal is to determine whether sweat collection from the thigh reduces the incidence of QNS compared to the forearm, which is the traditional site for sweat testing in infants. Additionally, the study aims to assess if the circumferential size of the upper and lower limbs influences the rate of QNS.

Secondary Outcome Measures

Name	Time	Method
Comparison of Chloride Concentration between Forearm and Thigh Sweat Collection in Infants	Chloride concentration will be measured immediately after sweat collection from both forearm and thigh during each session, with results recorded and analyzed following each collection.	The secondary objective of this study is to compare chloride concentration values between sweat collected from the forearm (upper limb) and the thigh (lower limb) in the same infant under 6 months of age. Sweat will be collected simultaneously from both sites using the Macroduct Advanced device. This comparison aims to determine if there is a significant difference in chloride levels between the two sites, and whether the anatomical site of sweat collection impacts the chloride concentration in the samples.

Trial Locations

Locations (1)

UZ Brussel; 🇧🇪 Jette, Brussels, Belgium