EGD is pretty quick. Upper endoscopy uses an optical device on a flexible, steerable tube to examine esophagus, stomach, & upper small bowel. Often, biopsies are taken to rule out barrett's esophagus, eosinophilic esophagitis, h.Pylori bacteria, celiac sprue. A diagnostic study as such takes less than 5 minutes, during which you are sedated. Therapeutics (dilation, cautery, polypectomy, etc.) adds a few minutes more.