An upper GI series is a standard series of fluoroscopic X-rays that radiologists take of your upper gastrointestinal tract (GI). Your upper GI includes your esophagus, stomach and duodenum. Fluoroscopy produces moving-picture X-rays that show your organs in action. The test can help your doctor find functional and structural abnormalities.
Your gastrointestinal tract is the pathway that food takes through your digestive system. It’s made up of a series of hollow organs that connect together to form a tube, beginning at your mouth and ending at your anus. “Upper GI” refers to your upper gastrointestinal tract. That means your esophagus (swallowing pipe), your stomach and the first part of your small intestine (duodenum).
The “series” refers to a series of fluoroscopic X-rays that are taken during the test. Fluoroscopic X-rays are like regular X-rays, except they move — they’re the “movie” version of the stills you may be familiar with. Fluoroscopic X-rays allow healthcare providers to see your organs in action. They also provide more visual detail on the surface of your organs than regular X-rays.
The upper GI series is one of several specific GI X-ray exams that use fluoroscopy to examine different sets of organs along your gastrointestinal tract. Your healthcare provider might order one or several of these exams, depending on which parts of your GI tract they want to study.
Your esophagus, stomach and duodenum are grouped together as your “upper GI tract” for a few reasons:
If you have symptoms related to your upper GI tract, your healthcare provider will want to investigate that particular part. An upper GI series gives your healthcare provider a look at the insides of your esophagus, stomach and duodenum, including the state of the tissues, any structural abnormalities and whether they’re functioning normally. This is often the first step in understanding what may be causing you symptoms in those parts.
Your doctor might order an upper GI series if you have unexplained symptoms such as:
Tissue changes in your organs, such as:
Structural problems in your organs, such as:
Functional problems in your organs, such as:
Chronic acid reflux (GERD) is often diagnosed by symptoms alone, but your healthcare provider can see certain physical signs that might indicate GERD through an upper GI series. They can see severe acid erosion in the tissues that line your GI tract, and they can see ulcers and strictures that might have been caused by acid reflux. They can also see if the muscle that is supposed to keep stomach acid out of your esophagus isn’t closing all the way.
Your healthcare provider can see tumors and tissues changes related to cancer through the upper GI series if they’re big enough to detect, but they won’t be able to tell if they’re cancerous or not. To diagnose cancer, they’ll have to take a tissue sample to test in the lab. They’ll do this through an upper endoscopy.
Both the upper GI series and the upper endoscopy (esophagogastroduodenoscopy) examine the upper GI tract. But the procedures are very different. Upper GI X-ray exams are a type of radiology, which means they use radiant energy to take pictures of your insides. (X-rays, ultrasounds and CT scans are different types of radiology healthcare providers use.) Radiology is non-invasive, which means it doesn’t actually enter your body. That’s why it’s usually the first tool healthcare providers turn to when trying and find out what’s going on in your body.
An endoscopy is a more specific but more invasive diagnostic procedure. An upper endoscopy takes pictures of your insides by inserting a tiny camera called an endoscope down your throat. This often requires patient sedation (anesthesia). An endoscopy can provide more visual detail than radiology, and it also has the advantage of allowing your healthcare provider to access your insides with tools attached to the endoscope. This means they can take a biopsy to confirm a diagnosis. But because it’s more invasive, it's usually used as a follow-up to radiology rather than a first resort.
X-ray technology: An X-ray sends beams of ionizing radiation through your body. Your tissues, bones and organs absorb the radiation at different levels, depending on how dense they are. Then the radiation that your body absorbs is reflected back to an X-ray detector. Denser parts like bones absorb more and look brighter on X-rays, while softer parts like tissues appear in shades of grey.
Fluoroscopic technology: Fluoroscopy works the same way, only instead of a brief flash of radiation, it sends a continuous beam for a period of seconds or minutes to create a short video. This means slightly more radiation exposure for you, but it’s considered a safe level in most circumstances. We absorb small levels of ionizing radiation from our environment every day.
Contrast: Fluoroscopic X-rays usually require a contrast agent to maximize their clarity. A contrast agent is an internal substance that helps your insides stand out in black-and-white images. Sometimes, you ingest this contrast agent, and sometimes, it’s injected into you. The upper GI series typically uses barium as a liquid contrast agent.
Barium: Barium is a thick, white and chalky substance that coats your insides to help them stand out in black and white. It isn’t absorbed by your gastrointestinal tract and goes right through you. During the upper GI series, you’ll drink a liquid barium solution throughout the test. When you drink it, your radiologist will be able to watch it progress through your upper GI tract and see how your organs respond.
Double contrast: In some cases, an upper GI series will also use gas as an additional contrast agent. This is called a double contrast study. Gas helps by expanding and separating the walls of your upper GI tract to better distinguish what’s inside. Gas also appears black on X-rays, which is how it adds contrast to the white barium. To introduce gas to your GI tract, you may be given a tablet or carbonated beverage to swallow.
Before scheduling: Discuss the test with your healthcare provider in advance to make sure you don’t have any risk factors that would make it unsafe for you. Let them know if you’ve had another X-ray exam or another significant exposure to ionizing radiation recently. They may want to schedule your exam for a later time to reduce your overall exposure. Also, be sure to let them know if you might be pregnant, and they’ll make alternative plans. Fetal radiation exposure is associated with birth defects.
Before the test: It’s important to have an empty stomach for the test. You’ll be asked not to eat or drink anything on the night before the test or the on the morning of the test. You may also be asked to stop certain medications temporarily, such as antacids.
The test can take anywhere from 30 minutes to two hours. In some people, the barium might take longer to move all the way through their duodenum (upper small intestine).
Typical positioning may include:
The test itself isn’t painful, but you may have a sedative if you want one. After the test, you might feel a little bloated or crampy from the barium as it works your way through your digestive system. You might experience some gas pain if you had double contrast. These symptoms should resolve in a day or so.
This test isn’t a good option for you if you:
Your radiologist will study your X-rays and send the results to your healthcare provider. Your healthcare provider will discuss the results with you. Some conditions may be diagnosed from the X-rays alone, while others may require follow-up testing.
A note from Cleveland Clinic
An upper GI series is a painless, non-invasive way to give your healthcare provider a look inside of your esophagus, stomach and duodenum (upper small intestine). Fluoroscopy allows radiologists to see your organs in motion and observe how well they’re working, as well as any abnormalities in the way they look. Your healthcare provider may be able to diagnose your unexplained symptoms based on the results of the test. If not, this test gives them solid leads to follow up on.
Last reviewed by a Cleveland Clinic medical professional on 02/14/2022.
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