A blindfolded endoscope traveling past a few patches of inflamed intestine walls.

Can Crohn's Disease and Ulcerative Colitis Be Missed on a Colonoscopy?

Reviewed by: HU Medical Review Board | Last Reviewed: November 2022

Getting an accurate diagnosis is important with any disease. A proper diagnosis helps ensure that you will be treated correctly. However, diagnosing inflammatory bowel disease (IBD) can be challenging. IBD includes Crohn's disease and ulcerative colitis (UC), 2 conditions that cause inflammation in the digestive tract.1,2

How are Crohn's disease and UC diagnosed?

If you have symptoms of IBD, reach out to your doctor. They will first review your symptoms and try to rule out other conditions. Symptoms of IBD include:1,2

Once other conditions are ruled out, your doctor may use blood, stool, or imaging tests to help make a Crohn's or UC diagnosis.1-3

What imaging tests are used for diagnosing Crohn's and UC?

Crohn's and UC cause sores (ulcers) and swelling in the gut. To make a diagnosis, your doctor needs to see your gut from the inside. There are several ways to do this, such as:1-3

  • Colonoscopy – In this exam, your doctor uses a thin, flexible tube with a camera on the end to view the colon. The tube is inserted through your anus.
  • Endoscopy – This exam also uses a thin tube and camera, but they go in through your mouth. This helps your doctor examine your upper digestive system.
  • Capsule endoscopy – This exam involves swallowing a pill that contains a small camera. The camera travels through your entire digestive system and is passed painlessly in your stool. On its way through your gut, it sends pictures to a receiver.

During these tests, your doctor may also take biopsies. These are small pieces of tissue that are analyzed in a lab. A biopsy can help confirm an IBD diagnosis and rule out other conditions.1,3

Can Crohn's or UC be missed on a colonoscopy and other tests?

Crohn's and UC are hard to diagnose. In some cases, a colonoscopy or endoscopy is not enough to get a clear diagnosis. This is why doctors often take a biopsy during these procedures so they can look at the tissue in more detail.1-3

You may also need other imaging tests to look for UC or Crohn's. These tests may include X-rays, ultrasounds, or MRIs. If none of them leads to a diagnosis, you may need another colonoscopy or endoscopy.1,2

Also, research shows that IBD often has effects beyond the digestive tract. It can impact nearly every organ system in the body. These effects would not show up on a colonoscopy, which can make them possible to miss.4

What is indeterminate colitis?

Sometimes, your doctor may believe you have IBD but be unable to determine whether you have UC or Crohn's. In this case, you may get a diagnosis of indeterminate colitis. This is also called inflammatory bowel disease unclassified (IBDU). Your doctor will likely continue to run tests and begin treatment for IBD.2

Note that there are many other conditions that can cause inflammation in the digestive tract. Other conditions that are similar to UC include nonspecific colitis and ischemic colitis. Colitis means inflammation of the colon. While these conditions cause inflammation, they do not cause ulcers. So, they are not considered IBD.2

If you have concerns about your diagnosis, talk with your primary care doctor or gastroenterologist. It may take time to achieve a correct diagnosis. But getting the right diagnosis is an important step in treating IBD.

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This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The InflammatoryBowelDisease.net team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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