If abnormalities appear on a barium x-ray, the physician may order follow up tests to diagnose problems with the gastrointestinal (digestive) system. Depending on symptoms, a physician may order one or more of the following tests of the upper GI tract:

• Endoscopy. The physician guides a fiber-optic viewing tube (endoscope) with a miniature camera on the end through the patient’s mouth to examine the esophagus or stomach for lesions, blockage or other problems. The camera sends back pictures of abnormalities that are viewed on a monitor. The physician can also use the endoscope to obtain tissue samples (biopsies) for analysis.
  
  
• Ultrasound.  A test that uses harmless sound wave to creates pictures that outline organs and tissues.  However, an ultrasound does not detail the lining of the GI system.  An abdominal ultrasound can show excess formation of fluid or abnormal size or shape of an organ. In addition, an ultrasound probe may be used during an endoscopy to determine the presence of and depth of penetration of cancer. The probe sends out very sensitive sound waves that penetrate deep into the tissues to reveal close-up images of the esophagus and nearby tissues.
  
  
• Esophageal pH test. This test measures the acidity in the throat. It can indicate acid reflux, the abnormal presence of stomach acid in the esophagus.
  
  
• Manometry. A manometer (tube lined with pressure gauges) guided down the throat measures the contractions of the esophagus (esophageal manometry) and/or stomach (gastric manometry). It may be used in suspected cases of gastroparesis or other conditions involving the nerves or muscles of the upper digestive system.
  
  
• Bernstein test (esophageal acid perfusion test). This test for esophagitis introduces a small quantity of acid in the esophagus through a nasogastric tube.
  
  
• Gastric emptying scan (GES). The patient eats food containing a tracer (a radioisotope, with a low, safe level of radiation). With the patient lying down, a scanning machine is placed above the abdomen for several hours. The tracer allows the machine to track the radioactivity in the stomach and show how fast the food exits the organ.
  
  
• Antroduodenal motility study. The patient is sedated or has the throat numbed. A tube is passed down the throat and through the stomach into the duodenum. Sensors in the tube measure the contractions of the digestive tract at rest and after a meal and reveal whether emptying of the stomach is delayed.

Other ways of testing for lower GI problems such as colon cancer include:

• Digital rectal exam. The physician carefully inserts a gloved, lubricated finger several inches into the rectum to feel for abnormalities.
  
  
• Flexible sigmoidoscopy. The physician inspects the interior of the rectum and the lower colon (the sigmoid) with a flexible, lighted tube called a sigmoidoscope. Deaths from cancer of the rectum and sigmoid colon are more than 50 percent lower among people who have had sigmoidoscopy, according to the CDC.
  
  
• Colonoscopy. A longer flexible, lighted tube with a camera lens called a colonoscope that allows a physician to inspect the rectum and entire colon. The device is connected to a video camera and monitor. The physician may pass a wire through the colonoscope to remove polyps with an electric current. Tissue samples can be taken for microscopic examination in a biopsy. For more information, see Colonoscopy.

A physician will be able to provide more details about the many types and definitions of barium x-ray tests, when they are needed, how they are performed and their risks and benefits.