Patients who experience swallowing difficulties, acid reflux, unexplained nausea and vomiting and a variety of other conditions may be asked to undergo an “upper GI series,” or gastroscopy screening – also known as an EGD for esophagogastroduodenoscopy. This painless procedure, performed with the patient under sedation, employs the use of a flexible, fiber-optic instrument called a gastroscope that is passed through the mouth and down into the esophagus, stomach and duodenum (first part of the small intestine). The scope allows your doctor to visualize and take pictures of the interior of these structures while looking for obstructions, ulcers, inflammation, strictures, polyps and tumors. It also allows the doctor to secure a tissue sample for biopsy under a microscope, and to stop any bleeding that may be occurring from enlarged veins. It is important to follow the instructions you are given prior to a gastroscopy procedure, including those pertaining to fasting eight or more hours ahead of time.