Capsule sponge test revolutionizes GERD diagnosis, reduces unnecessary endoscopies

By Dr. Chinta SidharthanReviewed by Benedette Cuffari, M.Sc.Dec 1 2024

Revolutionizing GERD diagnosis: how capsule sponge testing prioritizes high-risk patients while easing the strain on endoscopy services.

Study: Clinical application of capsule sponge testing in symptomatic reflux disease: a national prospective cohort study. Image Credit: Andrey Zhernovoy / Shutterstock.com

In a recent study published in the journal BMC Gastroenterology, researchers in the United Kingdom investigated the effectiveness of capsule sponge testing, a minimally invasive diagnostic tool, as a triage method for patients with gastroesophageal reflux disease (GERD).

GERD, Barrett’s esophagus, and cancer detection

GERD is a common condition characterized by chronic symptoms such as heartburn caused by gastric content regurgitation. Barrett’s esophagus, which describes changes in the lining of the lower esophagus due to chronic damage from stomach acid, is often associated with GERD. To date, Barrett’s esophagus is the only identified precursor to esophageal adenocarcinoma, a cancer with poor survival rates when diagnosed late.

Current guidelines recommend screening individuals for esophageal adenocarcinoma with certain risk factors. However, the primary diagnostic tool, upper gastrointestinal endoscopy, is associated with numerous limitations, including invasiveness, sampling errors, and high healthcare costs. Additionally, most endoscopies for GERD symptoms do not reveal significant pathology, thus contributing to resource strain.

The coronavirus disease 2019 (COVID-19) pandemic overwhelmed endoscopy services, creating a need for alternative diagnostic approaches. Capsule sponge testing, a noninvasive method, has been associated with high sensitivity for the detection of Barrett’s esophagus in controlled trials. However, its application in real-world settings, particularly as a triage tool for GERD, remains underexplored.

About the study

In the current prospective cohort study, researchers assess capsule sponge testing as a diagnostic triage tool for GERD patients referred for non-urgent endoscopy across 11 Scottish health boards between September 2020 and April 2023. Patients were referred from their primary care physician for evaluation of reflux symptoms without alarm features such as dysphagia or weight loss. Exclusion criteria included contraindications such as liver disease, pregnancy, or previous esophageal surgery.

The capsule sponge device, a gelatin-coated medical sponge on a string, was swallowed by patients under supervision. After five minutes, the capsule dissolved, releasing the sponge, which was retrieved by pulling the string to collect esophageal cells. Collected samples were analyzed for trefoil factor 3 (TFF3) expression, which indicated intestinal metaplasia, cellular atypia, and p53, which is associated with malignancy.

Data were also obtained from prospectively maintained databases and electronic patient records. These data consisted of demographic information, test results, and subsequent clinical management. Upper gastrointestinal endoscopy and biopsy results were also included for cases requiring follow-up care.

Statistical analyses were performed to evaluate the relationship between biomarker results and pathology findings and to determine the safety and efficacy of the capsule sponge device as a triage method. Upper gastrointestinal specialists or trained nurses managed patients undergoing capsule sponge testing through clinical assessments, either virtually or in person.

Study findings

Capsule sponge testing effectively identified GERD patients who required further investigation with upper gastrointestinal endoscopy. Among the 1,305 patients tested, samples obtained from 79.6% did not express any of the biomarkers, which led to the discharge of 70% of patients without additional procedures.

Of the 355 patients who underwent endoscopy, 16.6% were diagnosed with intestinal metaplasia, a precursor to Barrett’s esophagus, with 88.5% of these cases correlating with positive biomarker results. Thus, the capsule sponge test was associated with high specificity, especially for the TFF3 biomarker, in which positivity strongly correlated with intestinal metaplasia detected during the biopsy.

Although 10 patients with negative test results eventually presented with significant pathology, including malignancies, the overall rate of missed diagnoses was low at 0.9%. Moreover, endoscopic biopsies confirmed Barrett’s esophagus in 4.2% of the cohort, thus reinforcing the utility of the capsule sponge test in prioritizing high-risk cases for endoscopy.

The capsule sponge method significantly reduced unnecessary endoscopies, easing resource demands without compromising patient safety. Furthermore, patients with biomarker-positive samples were more likely to have significant endoscopic findings, thus supporting the utility of the capsule sponge test in effective risk stratification.

Importantly, clinical evaluations must continue to be performed, as capsule sponge testing can produce false negatives. Follow-up in patients presenting new symptoms is also crucial.

Conclusions

Capsule sponge testing is a minimally invasive and cost-effective approach to triaging GERD patients for endoscopy that significantly reduces unnecessary procedures while identifying high-risk cases. The current real-world study also demonstrated the efficacy of this method in diagnosing Barrett’s esophagus and prioritizing healthcare resources.

Although missed diagnoses occurred in rare cases, the study findings support the integration of capsule sponge testing into clinical practice when combined with thorough clinical assessments to ensure comprehensive patient care.