The capsule sponge test used in the BEST4 trials is EndoSign®. EndoSign® is an oesophageal cell collection device that is minimally invasive, well tolerated and can be administered by any health care professional. This is a second generation of the capsule sponge test initially referred to as Cytosponge, this version is easier to administer but the cell collection properties are identical.
FAQs about the device can be found on the manufacturer’s website here.
The ‘pill on a string test’ involves patients swallowing the 3cm dissolvable capsule whilst holding onto the string. After 7 minutes the capsule dissolves, allowing the contained sponge (polyester, medical grade foam) to expand. Using the string, the sponge is pulled from the stomach through the oesophagus to the mouth, collecting cells from the entire length of the oesophagus. The sponge is then put into a preservative which is stable at room temperate for shipment to the laboratory. The sample can be processed for the presence of Barrett’s biomarker Trefoil Factor 3 (TFF3) and other specific biomarkers such as p53 and atypia.
Over 15,000 patients have had a capsule sponge test as part of NHS pilots and >5,000 patients received the test as part of clinical trials (BEST1, 2, 3). It is well tolerated, with no reported serious adverse events. Sedation is not required, although local anaesthetic spray may be offered to patients to avoid discomfort upon retrieval of the sponge, but most patients prefer not to use spray since removal is so quick. There is a very small risk (less than 1 in 2000) of the thread detaching from the sponge; if this occurs, endoscopy can be used to remove it.
Healthcare professionals with clinical queries on BEST4 can contact us via email at cuh.best4.trial@nhs.net
For more general enquiries, please contact Best4enquiries@qmul.ac.uk
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