Crohn’s Disease Diagnosis

Key points

  • Crohn’s disease can affect people of all ages and genders.
  • Crohn’s is difficult to diagnose and multiple tests may be needed to find the best treatment for you.

How do I know if I have Crohn’s disease?

Crohn’s disease can affect anyone at any stage in their life but symptoms usually appear in teenagers and young adults. 

To know if you have Crohn’s disease you will need to be tested by a doctor. Symptoms of Crohn’s are similar to many other conditions so several tests will likely be needed before you can get a diagnosis. In many cases doctors will want to make sure that your symptoms aren’t caused by an infection or irritable bowel syndrome (IBS). Investigations help to work out which parts of your bowel are affected to determine the best treatment options for you. Tests may include: 

Blood tests: Used to find out if inflammation is present and if you have anaemia or low nutrition levels or signs of inflammation. 

Stool tests: Used to make sure your symptoms are not caused by an infection. Can also detect inflammation through a test for faecal calprotectin levels, which is a marker of white blood cells released from the inflammation of the gut lining. 

Endoscopy: Used to view the digestive system with an endoscope or tube with a camera and light at the end. Depending on the test, the camera may be inserted through the mouth or anus. A tissue sample (biopsy) may also be collected and examined. There are also endoscopic capsules that can be swallowed to capture images of the entire small bowel. 

There are different types of endoscopies that may be used for Crohn’s disease. For example:

  • Upper GI endoscopy: The endoscope will enter your mouth or nose to examine your throat, stomach and the start of your small intestine.
  • Colonoscopy: Used to see the entire large intestine and the end of the small intestine and enters through the anus.
  • Sigmoidoscopy: Used to examine the rectum and lower part of the large intestine and enters through the anus.

Bowel imaging and scans: Used to discover inflammation and complications like strictures (narrowing of the gut), fistulae or abscesses. MRI (Magnetic Resonance Imaging) uses magnets and radio waves while CT (Computerised Tomography) scans use a series of quick x-rays to build a 3D image of the target area. Some centres may also use intestinal ultrasound. 

Crohn’s disease is a disease that will change over time. Tests may be used again to monitor your disease and to see if the current treatment is working or if complications have developed.