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

Official title

Sweat Testing in Infants: a Comparative Study Investigating the Collection of Sweat on the Upper Limbs Compared to the Lower Limbs

Overview

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.

Interventions

• Device Macroduct Advanced
  Sweat stimulation and collection using the Macroduct Advanced system on two anatomical sites (forearm and thigh) in infants under 6 months of age.

Primary outcome measures

• Comparison of Sweat Collection Sites: Forearm vs. Thigh in Infants (Primary Outcome: QNS Rate) [Time frame: 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.]

Secondary outcome measures (1)

• Comparison of Chloride Concentration between Forearm and Thigh Sweat Collection in Infants [Time frame: 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.]

Eligibility criteria

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)

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Screening

Study locations

Belgium · 1 center

• UZ Brussel — Jette

Publications

• McColley SA, Elbert A, Wu R, Ren CL, Sontag MK, LeGrys VA. Quantity not sufficient rates and delays in sweat testing in US infants with cystic fibrosis. Pediatr Pulmonol. 2020 Nov;55(11):3053-3056. doi: 10.1002/ppul.25027. Epub 2020 Aug 25. PMID 32797669
• Taylor NA, Machado-Moreira CA. Regional variations in transepidermal water loss, eccrine sweat gland density, sweat secretion rates and electrolyte composition in resting and exercising humans. Extrem Physiol Med. 2013 Feb 1;2(1):4. doi: 10.1186/2046-7648-2-4. PMID 23849497
• Vermeulen F, Lebecque P, De Boeck K, Leal T. Biological variability of the sweat chloride in diagnostic sweat tests: A retrospective analysis. J Cyst Fibros. 2017 Jan;16(1):30-35. doi: 10.1016/j.jcf.2016.11.008. Epub 2016 Dec 22. PMID 28017620
• Massie J, Greaves R, Metz M, Wiley V, Graham P, Shepherd S, Mackay R. Australasian Guideline (2nd Edition): an Annex to the CLSI and UK Guidelines for the Performance of the Sweat Test for the Diagnosis of Cystic Fibrosis. Clin Biochem Rev. 2017 Nov;38(3):115-130. No abstract available. PMID 29332976
• LeGrys VA, Briscoe D, McColley SA. Sweat testing: specimen collection and quantitative chloride analysis. CLSI Guideline 2019;C34
• Cirilli N, Southern KW, Barben J, Vermeulen F, Munck A, Wilschanski M, Nguyen-Khoa T, Aralica M, Simmonds NJ, De Wachter E; ECFS Diagnostic Network Working Group. Standards of care guidance for sweat testing; phase two of the ECFS quality improvement programme. J Cyst Fibros. 2022 May;21(3):434-441. doi: 10.1016/j.jcf.2022.01.004. Epub 2022 Jan 19. PMID 35063396

Identifiers

NCT: NCT06902363 · 24147_Zweetteststudi

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗