One-Hour Esophageal String Test: A Nonendoscopic Minimally Invasive Test That Accurately Detects Disease Activity in Eosinophilic Esophagitis

Abstract

OBJECTIVES:Eosinophilic esophagitis (EoE), a chronic food allergic disease, lacks sensitive and specific peripheral biomarkers. We hypothesized that levels of EoE-related biomarkers captured using a 1-hour minimally invasive Esophageal String Test (EST) would correlate with mucosal eosinophil counts and tissue concentrations of these same biomarkers. We aimed to determine whether a 1-hour EST accurately distinguishes active from inactive EoE or a normal esophagus.METHODS:In a prospective, multisite study, children and adults (ages 7–55 years) undergoing a clinically indicated esophagogastroduodenoscopy performed an EST with an esophageal dwell time of 1 hour. Subjects were divided into 3 groups: active EoE, inactive EoE, and normal esophageal mucosa. Eosinophil-associated protein levels were compared between EST effluents and esophageal biopsy extracts. Statistical modeling was performed to select biomarkers that best correlated with and predicted eosinophilic inflammation.RESULTS:One hundred thirty-four subjects (74 children, 60 adults) with active EoE (n = 62), inactive EoE (n = 37), and patient controls with a normal esophagus (n = 35) completed the study. EST-captured eosinophil-associated biomarkers correlated significantly with peak eosinophils/high-power field, endoscopic visual scoring, and the same proteins extracted from mucosal biopsies. Statistical modeling, using combined eotaxin-3 and major basic protein-1 concentrations, led to the development of EoE scores that distinguished subjects with active EoE from inactive EoE or normal esophagi. Eighty-seven percent of children, 95% of parents, and 92% of adults preferred the EST over endoscopy if it provided similar information.DISCUSSION:The 1-hour EST accurately distinguishes active from inactive EoE in children and adults and may facilitate monitoring of disease activity in a safe and minimally invasive fashion.

Eosinophilic gastrointestinal disorders and allergen immunotherapy: Lights and shadows

“…Providers should be aware of the risk of developing EGIDs, mostly during OIT. When recurrent gastrointestinal symptoms are observed during food AIT or SLIT, the diagnosis of EGIDs should be promptly considered, and patients should undergo GI endoscopy or less invasive diagnostic tools, such as the esophageal string test 76,77 . Fortunately, these complications seem to be reversible by early diagnosis and cessation of OIT and SLIT.…”

Eosinophilic esophagitis, Barrett’s esophagus and esophageal neoplasms in the pediatric patient: a narrative review

“…The Esophageal String Test (EST) is a minimally invasive technique that utilizes the Enterotest string device which is a gelatin capsule containing a nylon string that is swallowed and later withdrawn through the mouth. EST can detect active EoE inflammation by measuring biomarkers such as eotaxin-3 and major basic protein-1 (8,17,18). Luminal concentrations of eosinophil-associated proteins obtained by EST were found to correlate with esophageal mucosal eosinophilic inflammation (17,18).…”

“…EST can detect active EoE inflammation by measuring biomarkers such as eotaxin-3 and major basic protein-1 (8,17,18). Luminal concentrations of eosinophil-associated proteins obtained by EST were found to correlate with esophageal mucosal eosinophilic inflammation (17,18). A prospective, multisite study evaluating 134 subjects (both pediatric and adult) by Ackerman et al demonstrated that a 1-hour EST accurately distinguishes active vs. inactive EoE in a less invasive and safe manner compared to endoscopic examination with biopsies (18).…”

“…Luminal concentrations of eosinophil-associated proteins obtained by EST were found to correlate with esophageal mucosal eosinophilic inflammation (17,18). A prospective, multisite study evaluating 134 subjects (both pediatric and adult) by Ackerman et al demonstrated that a 1-hour EST accurately distinguishes active vs. inactive EoE in a less invasive and safe manner compared to endoscopic examination with biopsies (18). Unsedated transnasal endoscopy (uTNE) utilizes a small flexible endoscope for sampling esophageal mucosa and can be performed without anesthesia or sedation in select patients.…”

Steroid Eluting Esophageal-Targeted Drug Delivery Devices for Treatment of Eosinophilic Esophagitis

“…A drug-eluting string could be swallowed, allowing a sustained release of drug along the entire length of the esophagus, perhaps during an overnight dwell, rather than the usual one-time bolus from a swallowed medication. While the minimally invasive esophageal string test has been used to absorb inflammatory factors related to EoE and characterize disease activity [ 11 , 12 , 13 ], there are no reports of delivering medication to the esophagus in this manner. A recent report outlined how a membrane deployed from a capsule might also target drug delivery to the esophagus.…”