• An upper gastrointestinal series is an x-ray test used to define the anatomy of the upper digestive tract.
• Women who are or may be pregnant should notify the doctor requesting the procedure and the radiology staff.
• An upper gastrointestinal series involves filling the esophagus, stomach, and small intestines with a white liquid material (barium).

An upper gastrointestinal (GI) series (barium swallow), is a radiological test that is used to visualize the structures of the upper digestive system - the esophagus, stomach and duodenum. (If visualization of the remaining parts of the small intestine is necessary, a small bowel follow through  can be added to the test.) These structures are observed during the examination, and the images are also  saved for further review on X-ray film or as digital images. An upper GI series can reveal conditions such as ulcers, tumors, hiatal hernias, scarring, blockages, and abnormalities of the muscular wall of the gastrointestinal tissues.

Any x-ray test procedure involves some risk from radiation exposure. The radiation exposure is minimized by standard techniques that have been assigned and approved by national and international radiology committees and councils. Radiology technicians are certified by national certifying boards.

Patients who are or may be pregnant should notify the requesting practitioner and radiology staff, as there is potential risk of harm to the fetus with any radiation exposure.

A radiology technologist guides the patient through the upper GI series along with a radiologist (a physician trained in performing and interpreting x-rays). Because an upper GI series involves interpreting images of the gastrointestinal system, it is important that any materials or objects internally or externally that could potentially interfere with interpretation of the X-ray film be avoided. Therefore, patients are requested not to eat or drink anything from four to eight hours before the procedure. Patients also are asked to remove their clothing and all metallic objects such as jewelry.

• A patient will be positioned behind X-ray equipment called a fluoroscope for X-ray exposure.
• The patient then is asked to swallow a liquid that contains barium. The barium fills and then coats the lining of the intestinal tract making the adjacent esophagus, stomach and duodenum visible. (X-rays of the stomach and intestine done without barium provide very little detail and information.)
• X-ray images are obtained at different angles through the chest and abdomen. The X-ray machine (fluoroscope) produces these images by sending X-ray radiation through the tissues of the body to a film on the opposite side of the patient's body. As the radiation penetrates the body, it is absorbed in varying amounts by different body tissues.
• Due to differences in their composition, the different organs and certain abnormalities and conditions all become visible on the X-ray film, by blocking the penetration of the X-ray beam to varying degrees.
• After development of the film, an image of the organs is revealed. The radiologist then examines the X-rays and can identify various normal and abnormal structures of the gastrointestinal system.
• If needed, further enhancement of the different structures can be obtained by having air as well as barium in the stomach. This is accomplished by swallowing baking soda crystals.

As barium passes through the digestive system, constipation can result, especially in patients prone to constipation. Therefore, it generally is advisable that patients who undergo an upper GI series drink extra fluids after the test and consider a laxative to relieve the bowels of the barium if the barium is not eliminated completely within the next day or two. As it is passing in the stool, barium has a whitish appearance that maybe apparent for several days after the test.

After the radiology technician develops the X-ray film or digital image, it is transferred to the radiologist. This physician interprets the films. The radiologist then generates a report that is transmitted to the physician who requested the test. The radiologist and the practitioner often review the findings together. The practitioner can review the results of the upper GI series with the patient and can proceed with therapy or discuss whether other tests may be necessary.