Upper GI test The upper GI test is used to examine the esophagus, stomach and part of the small intestine. For this test, the patient drinks a contrast solution that contains barium. The barium solution is sweetened and flavored, but does taste chalky. There will be both thick and thin mixtures of the barium solution you'll be asked to drink (usually totaling 12 to 14 ounces). The doctor or assistant will tell you when to take sips of the solution. As the barium passes through the digestive tract, it provides an outline of the swallowing process as well as the esophagus, stomach and part of the small intestine. The fluoroscope is held over the part of the body being examined and transmits continuous images to the video monitor. This test is used to diagnose hiatal hernias, ulcers, tumors, diverticulitis, esophageal varices, obstruction, narrowing, or enteritis (inflammation of the small intestine lining). It may also be used to determine the causes of swallowing problems, reflux, abdominal pain, diarrhea, unexplained vomiting or weight loss or bleeding. Lower GI test The lower GI test is used to examine the large intestine and the rectum. For this test, barium is introduced gradually into the colon through a tube inserted into the rectum. As the barium passes through the lower intestine, it provides an outline of the intestinal wall. The fluoroscope is held over the part of the body being examined and transmits continuous images to the video monitor. This test is used to detect polyps, tumors, diverticulitis, gastroenteritis, irritable colon, ulcerative colitis or other causes of abdominal pain, or blood, mucus or pus in the stool. . Upper GI test The upper GI test is used to examine the esophagus, stomach and part of the small intestine. For this test, the patient drinks a contrast. or weight loss or bleeding. Lower GI test The lower GI test is used to examine the large intestine and the rectum. For this test, barium is introduced gradually into the colon through. intestine lining). It may also be used to determine the causes of swallowing problems, reflux, abdominal pain, diarrhea, unexplained vomiting or weight loss or bleeding. Lower GI test