Cytosponge for Gastric Intestinal Metaplasia

This study tests whether a swallowable sponge capsule called the Cytosponge (swallowed, then pulled back up by a string) can detect pre-cancerous changes in the stomach lining (gastric intestinal metaplasia) as effectively as a traditional endoscopy. **You may be eligible if...** - You are 18 or older and medically fit for an endoscopy - You have been previously diagnosed with gastric intestinal metaplasia (a pre-cancerous change in the stomach lining) — if joining as a "case" participant - You have upper digestive symptoms and are referred for endoscopy — if joining as a "control" participant **You may NOT be eligible if...** - You have been diagnosed with a tumor of the throat, esophagus, or stomach (T2 or higher) - You have Barrett's esophagus, esophageal varices, strictures, or need esophageal dilation - You take blood thinners that cannot be safely stopped before the procedure - You have trouble swallowing Talk to your doctor to see if this trial is right for you.