The Esophageal String Test as a Diagnostic Screening Tool for Eosinophilic Esophagitis Among Africans With Dysphagia in Mali and the United States

Launched by NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES (NIAID) · Jun 18, 2025

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ClinConnect Summary

This clinical trial is exploring a new, easier way to diagnose a condition called eosinophilic esophagitis (EoE), which causes inflammation in the esophagus—the tube that carries food from the mouth to the stomach. Right now, diagnosing EoE usually requires an endoscopy, where a thin tube is inserted down the throat to look at the esophagus and take tissue samples. This study is testing a simpler and less expensive method called the Esophageal String Test (EST). In this test, participants swallow a small capsule attached to a string that collects fluid from the esophagus over an hour. The fluid is then analyzed to see if it can detect EoE as well as the traditional endoscopy.

Adults between 18 and 65 years old who were born in Africa and have symptoms like difficulty swallowing (dysphagia) may be eligible to join. Participants will provide samples like blood, stool, urine, and skin, answer questions about their health and lifestyle, and bring a sample of their drinking water for testing. They will first undergo the EST and later have the standard endoscopy for comparison. Afterward, they’ll discuss their results with the study team either in person, online, or by phone. This study could help make diagnosing EoE easier and more accessible, especially for people of African descent experiencing swallowing problems.

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Eligibility criteria

• * INCLUSION CRITERIA:
• In order to be eligible to participate in this study, an individual must meet all of the following criteria:
• • 1. Able to provide informed consent.
• • 2. Aged 18 to 65 years.
• • 3. Born in the African continent and of African ancestry.
• • 4. Exhibiting symptoms of dysphagia and/or prior history of food impaction.
• • 5. Undergoing clinically indicated endoscopy at the NIH Clinical Center or Centre Hospitalier Universitaire Gabriel Toure and willing to provide research samples and data.
• EXCLUSION CRITERIA:
• An individual who meets any of the following criteria will be excluded from participation in this study:
• • 1. Recent steroid use (systemic or swallowed/topical corticosteroid) within 4 weeks prior to endoscopy.
• • 2. Recent use of dupilumab (Dupixent) within the last 6 months.
• 3. Recent use of other biologic medications (within either 6 months or 5 half-lives, whichever is longer). Examples of biologic medications include:
• • 3a. mepolizumab (Nucala)
• • 3b. reslizumab (Cinqair, Cinqaero)
• • 3c. benralizumab (Fasenra)
• • 3d. cendakimab
• • 3e. tezepelumab (Tezspire)
• • 3f. barzolvolimab
• • 4. Individuals suffering from a bleeding diathesis (e.g., hemophilia, severe thrombocytopenia).
• • 5. Current use of anticoagulant medications.
• • 6. Pregnancy.
• • 7. Treatment with another investigational drug or other investigational intervention within 6 months or 5 half-lives whichever is longer.
• 8. Individuals with a known history of any of the following:
• • 8a. eosinophilic esophagitis
• • 8b. esophageal stricture unable to be passed with an upper endoscope
• • 8c. esophageal cancer
• • 8d. esophageal motility disorder (e.g., achalasia)
• • 8e. esophageal varices
• • 8f. esophageal or gastric surgery including fundoplication
• • 8g. neurologic cause of dysphagia (e.g., stroke, Parkinson s disease, etc.)
• • 8h. allergy to gelatin
• • 8i. inability to swallow pills
• • 9. Any condition that, in the investigator s opinion, places the individual at undue risk by participating in the study.
• • Co-enrollment guidelines: Co-enrollment in other trials is restricted, other than enrollment on observational studies. Consideration for co-enrollment in trials evaluating the use of a licensed medication will require the approval of the principal investigator in consultation with the medical monitor. Study staff should be notified of co-enrollment on any other protocol as it may require the approval of the principal investigator.