Ulcerative colitis is a condition that causes inflammation along the lining of your colon or rectum. This inflammation leads to sore spots called ulcers.

Common symptoms of ulcerative colitis include:

Typically, it’s diagnosed either between the ages of 15 to 30 or between 50 and 70.

The only way to know for sure you’re dealing with ulcerative colitis is to undergo endoscopy with a tissue biopsy.

Endoscopic procedures involve inserting a long flexible tube with a camera into your anus to exam your colon. A tissue biopsy is when a doctor removes a small sample of tissue to be analyzed in a lab.

Along with an endoscopy, a doctor will likely recommend a blood test and stool sample to rule out conditions that cause similar symptoms. In some cases, imaging techniques like X-rays or CT scans may be used.

In this article, we’ll examine the various tests used to diagnose ulcerative colitis in detail.

Ulcerative colitis is one of the two main types of inflammatory bowel disease (IBD), along with Crohn’s disease. Symptoms of these conditions are similar and can be difficult to differentiate.

Your doctor will diagnose ulcerative colitis based on your symptoms using supportive evidence from an endoscopy, tissue biopsy, and negative stool examination, while ruling out infectious disease.

Two types of endoscope tests may be used to help diagnose ulcerative colitis. We’ll look at these two tests in more detail below.


A colonoscopy is a procedure where a doctor inserts a long, flexible fiber-optic camera into your bowel to search for signs of inflammation and ulcers. The procedure typically takes about half an hour.

During the procedure, you’ll likely be given a sedative and told to lie on your side. A doctor will insert the colonoscope gently into your anus, through your rectum, and into your colon. They will be able to see an image of your colon on a monitor during the procedure.

Your doctor can use a special instrument on the end of the colonoscope to take a small tissue sample from the wall of your colon. This sample will be sent to a lab to examine it for inflammatory markers that indicate you have ulcerative colitis.

Sometimes, a doctor may recommend chromoendoscopy. During this type of colonoscopy, the walls of your colon will be covered with a blue dye to help identify abnormalities.

Flexible sigmoidoscopy

A flexible sigmoidoscopy, also just called sigmoidoscopy, is another type of exam that uses a long, thin tube with a camera on it to exam your colon.

The procedure is similar to a colonoscopy. but it’s less invasive. It only exams the part of your colon nearest to your rectum called the sigmoid colon, which is about 20 inches long.

The procedure usually takes about 15 minutes.

Along with an endoscopy and tissue biopsy, a doctor will likely give you a number of other tests to rule out other conditions.

Ulcerative colitis blood test

A blood test can potentially rule out an infection or anemia. Anemia is a condition when your red blood cell count is too low. A blood test can also help a doctor look for markers that show if your body is dealing with inflammation that may be a sign of ulcerative colitis.

Stool sample tests

During a stool sample, also called a stool culture, a doctor will collect a sample of your stool. The sample will be sent to a laboratory where it can be analyzed to see if you’re dealing with gastroenteritis.

Gastroenteritis is an infection of your stomach and intestines that can sometimes cause similar symptoms to that of ulcerative colitis. It may be caused by a bacterial, viral, or parasitic infection.

Imaging tests

If you have severe ulcerative colitis symptoms, or if your doctor suspects that you may have developed complications, they may recommend:

  • X-ray. An X-ray can help see if you’ve developed complications like a hole in your colon.
  • CT scan. A CT scan may help your doctor understood the extent of your inflammation and whether you have any complications.
  • CT enterography. A CT enterography can provide a more detailed look at your colon than a conventional X-ray or CT scan.
  • MR enterography. An MR enterography is a radiation-free test that can help create a detailed image of your bowel and find inflammation.

It’s not known what causes inflammatory bowel diseases such as ulcerative colitis. However, your genetics are thought to play a role. About 8 to 14 percent of people with inflammatory bowel disease have a family history of the disease.

If you have a parent or sibling who has ulcerative colitis, your risk increases 400 percent. Ulcerative colitis also has a higher incidence in people with Jewish heritage.

Currently, there’s no genetic test routinely performed to check for ulcerative colitis.

The company Prometheus has developed a test that uses a combination of serological, genetic, and inflammation testing to help diagnosis IBD. The latest research has found that it isn’t robust enough to be an initial test for IBD, but it may help doctors confirm their diagnosis.

If you think you may have ulcerative colitis, see a doctor. They will likely start by asking you questions about your medical history and whether anybody in your family has inflammatory bowel disease.

They can also perform a physical exam, blood test, and stool sample test.

If they suspect you have ulcerative colitis, they can refer you to a specialist for an endoscopy and further testing.

Ulcerative colitis is a condition that causes inflammation and ulcers along the walls of your colon. An endoscopy and tissue sample of your colon are needed for a doctor to differentiate ulcerative colitis from other similar conditions.