Lower GI Series

Reviewed by: HU Medical Review Board | Last reviewed: June 2016. | Last updated: June 2017

A lower GI series, also called a barium enema, is an x-ray exam that is used to diagnose a number of conditions that affect the large intestine. In the diagnosis of irritable bowel syndrome (IBS), a lower GI series is used to discover other conditions that may be causing the digestive symptoms the patient is experiencing. A patient with IBS would have a normal finding on a lower GI series given that IBS is considered a functional bowel disorder and therefore, does not show any obvious intestinal damage.

When a patient comes in complaining of abdominal pain, chronic diarrhea, constipation, or unexplained weight loss, a lower GI series may be used to help diagnose the cause of these symptoms. Diarrhea, constipation and abdominal pain are often present in cases of IBS, and these symptoms may prompt a healthcare professional to order a lower GI series. If the patient also presents with bleeding from the anus, a lower GI series is used to evaluate the presence of hemorrhoids or another physical cause.1,2

In the case of IBS, the findings of a lower GI series would be normal. The lower GI series can detect other conditions that may be causing the patient’s gastrointestinal symptoms, such as:

  • Cancerous growths, such as colon cancer
  • Diverticula (small pouches in the colon)
  • A fistula (an abnormal passage between two organs in the body, often found in the areas around the rectum and anus)
  • Inflammation of the intestinal lining, such as in ulcerative colitis or Crohn’s disease
  • Polyps (small growths in the lining of the intestines)
  • Ulcers (sores on the intestinal lining)
  • Blockages of the large intestine1,2

What to Expect

Prior to the lower GI series, the patient receives instructions for how to cleanse their colon, as the colon must be completely clear to enable accurate results with the x-ray. This cleansing process usually includes an enema or laxatives, and the patient is asked to be on a clear liquid diet before the test.2

During the test, the patient lies on their back on the x-ray table, and an x-ray image is captured. Next, the patient will lie on their side and a lubricated tube is placed into the rectum. Through the tube, a liquid solution of barium sulfate is introduced into the colon. Barium is a white, chalky powder that, when mixed with water, produces a white liquid that appears white on an x-ray.3 This solution acts as a contrast material that allows visibility of different areas of the colon on the x-ray. In some cases, a small amount of air is also delivered into the colon to expand it. This is called a double-contrast barium enema. 2

Once the solution (and air, if necessary) is in the patient’s colon, the patient will be moved in different positions in order to take a series of x-ray images. The enema tube is removed after the images have been taken and the patient is allowed to empty their bowels and as much of the barium solution as possible. The solution and air may create a feeling of fullness, cramping and some discomfort. It is normal to experience white stools for a few days following the lower GI series, and patients are encouraged to drink extra fluids for two to four days following the procedure.2

Additional Tests for IBS

There are a number of diagnostic tests that may be used to diagnose IBS because there is no single test that confirms the condition. Many of the tests confirm that other conditions or diseases do not cause the patient’s symptoms. This testing process can be frustrating and disheartening to patients, who are looking for an answer for their symptoms. Other tests that are commonly used to diagnose IBS include a physical exam with a symptom history, stool analysis, blood tests, breath tests, a colonoscopy and a CT scan.

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