2016-06-24 13:54:11 UTC

IBD 104: Getting Tested for Crohn's Disease

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There are many tests your gastroenterologist can do to find out if you have Crohn’s disease. First, he or she will take your past health info, listen to your symptoms, and do an exam to feel and listen to your belly. No one test makes the diagnosis, but testing is used to confirm the gastroenterologist’s clinical suspicion that Crohn’s disease is causing symptoms.


Blood Tests


  • Your doctor will look for anemia (low iron in your blood, which can make you feel weak and tired), caused by bleeding. 
  • Blood tests can show signs of inflammation or infection somewhere in the body, like a high white blood cell count and other markers of inflammation.
  • Blood tests can be done at your doctor’s office or in a lab.


Stool Tests


  • Stool tests are done to make sure there aren’t other GI health problems, such as infection, causing symptoms.
  • Stool tests can show if there is bleeding in the intestines and may confirm if inflammation is present.
  • Your doctor will give you a special holder for the stool, which is then returned to your doctor or a lab.

The below tests are done in your doctor’s office, an outpatient center or a hospital. These tests can be used to find Crohn’s disease or to rule out other health issues, such as ulcerative colitis, irritable bowel syndrome (IBS), diverticulitis or cancer.




  • You will be given medicine to make you feel relaxed and sleepy during this test. 
  • A colonoscopy involves looking at the colon from inside the body using a long, thin (about the width of your little finger), flexible tube with a tiny camera on the end, through which the doctor can view your whole colon and rectum for inflammation, swollen tissue, ulcers or polyps (mushroom-like or flat growths on the inside wall of the colon or rectum).
  • If the doctor thinks it might be Crohn’s disease, he or she will also do a biopsy (taking a small piece of tissue to look at under the microscope) during the colonoscopy. This is not something you will be 
  • able to feel. 
  • You might feel some pressure during the exam and there may be some cramping afterward, but you most likely will not feel a thing during this test. 
  • You will need to “prep” before this test to clean out your bowel so your doctor can see clearly.
    • Follow the instructions given to you by your doctor to do this.
  • Since you will be given medicine to make you sleepy, you will need someone to take you home and you won’t be able to go to work that day. The next day, most people go back their usual activities.


Upper GI Endoscopy and Enteroscopy


  • An endoscopy or enteroscopy is done to look inside your gastrointestinal (GI) tract to see if there is inflammation or ulcers and to get a small piece of the tissue (biopsy) from your small intestine to see if Crohn’s disease is present.
  • You will be given medicine to block pain and make you feel relaxed and sleepy, so you won’t feel much during the test. 
  • During the endoscopy, your gastroenterologist will use a long, thin (about the width of your little finger), flexible tube with a tiny camera on the end to look inside. 
  • The tube is passed through the mouth into the small intestine as your gastroenterologist does a careful exam.


Small Bowel Capsule Endoscopy


  • A capsule endoscopy is a way for your doctor to see inside your GI tract and look at the lining of the small intestine.
  • Unlike an upper GI endoscopy or a colonoscopy, this test uses a camera inside a pill-like capsule.
  • You will swallow the pill (which is just over 1-inch long and less than ½-inch wide) at your doctor’s office.
  • Once swallowed, it will travel through your GI tract, sending images to a special device for your doctor to review.
  • You will be awake and active during this test, though you will not feel the capsule. The capsule will leave your body naturally through a bowel movement.


Computerized Tomography (CT) Scan and MRI Enterography


  • These tests use both X-rays and computer technology to make clear images for your doctor to see your GI tract.
  • You will need to drink a mixture, which helps your doctor see your GI tract more clearly on the images. You may also be injected with a dye to help, as well.
  • You will not be put to sleep for this test.
  • This test can find Crohn’s disease and complications from the disease.


Upper Gastrointestinal (GI) and Small Bowel Series


  • This test uses X-rays to look at your upper GI tract.
  • During this test, you will sit or stand in front of an X-ray machine and drink a thick liquid called barium. The barium will coat your esophagus (the tube that links your mouth and stomach), stomach and small intestine so your doctor can see them more clearly in the images.
  • You will not be put to sleep for this test.
  • You should not eat or drink before this test. 
  • This test may cause bloating (swelling) or upset belly for a short time. The barium may cause your stool to be white or light-colored. You may be instructed to take a laxative after the test to make sure that the barium is passed and does not cause severe constipation (hard stool or trouble passing stool).

Talk to your doctor about which test is best for you. Your doctor will give you specific instructions for how to get ready for your test for Crohn’s disease.


© AGA, September 2017

©AGA, July 2016

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