Crohn’s disease is a type of inflammatory bowel disease. It is a chronic condition that can cause inflammation anywhere in the gastrointestinal (GI) tract, which runs from the mouth to the anus. However, this condition most often affects the small intestine.

There is no single test to diagnose Crohn’s disease. A doctor might need to order a few different tests to confirm a diagnosis of this condition.

Keep reading to learn more about the different tests for diagnosing Crohn’s disease.

a woman having a blood test for Crohns diseaseShare on Pinterest
A blood test can help a doctor diagnose Crohn’s disease.

A doctor will often order an assortment of tests to help diagnose Crohn’s disease. These tests may include the following:

Blood tests

Doctors may conduct a blood test to search for signs of infection, anemia, or inflammation relating to Crohn’s disease.

Stool tests

A stool test can help identify signs of the disease in the stool, such as mucus or blood.

Imaging tests

A doctor might order an imaging test, such as an X-ray, CT scan, or MRI scan, to get a picture of the person’s internal structures. A CT or MRI scan might require the person to drink a contrast solution or receive contrast intravenously.

Doctors often use a special imaging test called an upper GI series to visualize the upper GI tract more clearly. This test involves the use of X-rays, fluoroscopy, and barium.

A person will drink the barium solution, and the radiologist will then track its movement through the upper GI tract using an X-ray.


Endoscopic procedures can involve endoscopy of the upper GI tract or a colonoscopy to visualize the lower GI tract.

In an upper GI endoscopy, a doctor uses a flexible, lighted tube with a camera on the end. The endoscope passes through the esophagus and into the stomach and small intestine. The doctor is then able to see inside the small intestine and look for any signs of Crohn’s disease.

A person might also need to undergo a capsule endoscopy in which they swallow a capsule that contains a tiny camera. The capsule passes through the GI tract and captures images, which it sends to a receiving device.

The person will easily pass the capsule during a bowel movement. A doctor can then download the images from the camera and review them.

In some cases, a doctor will recommend a colonoscopy. This test also involves a flexible, lighted tube with a camera on the end, which is called a colonoscope. The doctor inserts the colonoscope into the anus and carefully guides it through the rectum and large intestine. The doctor will be able to look for signs of Crohn’s disease or any other concerning issues.

During an endoscopy or colonoscopy, a doctor can take a biopsy of tissue in the GI tract and send it to the pathology laboratory for further testing. Biopsies can help diagnose Crohn’s disease or another condition, such as colon cancer.

Both types of endoscopic procedure will take place under sedation.

Before undergoing any test for Crohn’s disease, a person should speak to a doctor about the risks and benefits of the procedure and what to expect.

Blood or stool tests

These tests do not typically require any special preparation. A person should ask their doctor whether they need to avoid eating for a certain period before a blood test.

For a stool test, a person will receive specific instructions regarding the collection of the sample and how to send it for analysis.

Imaging tests

A person may also have to avoid eating for some time before an imaging test. A doctor should advise them as such if this is the case. Imaging tests do not usually cause discomfort, but they will often require a person to take oral contrast dye or receive it intravenously.

Endoscopic tests

A person can expect to receive sedatives and pain relievers before endoscopic testing. Therefore, they should bring a family member or friend to drive them home.

A colonoscopy requires a person to do a bowel prep the day before the procedure. The doctor will give specific instructions on how to complete this.

After giving someone a diagnosis of Crohn’s disease, a doctor will prescribe treatment. The treatment plan may include medication, diet changes, and surgery.


Medications do not cure Crohn’s disease, but they help manage the symptoms and prevent further complications.

Medications for Crohn’s disease include:

  • aminosalicylates, such as sulfasalazine, to control inflammation
  • corticosteroids, including prednisone, to control inflammation and suppress the immune system
  • immunomodulators, which include methotrexate, to suppress the immune system
  • biologic therapies, such as adalimumab, to neutralize proteins that the immune system makes

Dietary changes

A doctor might prescribe dietary changes for a person with Crohn’s disease. These changes can include:

  • avoiding high fiber foods
  • drinking more water
  • avoiding carbonated drinks
  • eating smaller meals

Read about some great snack tips and recipes for Crohn’s disease here.


Some people with Crohn’s disease may require surgery at some point. Surgery does not cure Crohn’s disease, but it can help treat complications, which can include bleeding, fistulas, and intestinal obstructions.

If the disease is severe, or there are complications, a doctor may decide to remove a part of the small intestine, large intestine, or rectum surgically.

Read more about Crohn’s disease surgery here.

Once a person has received a diagnosis of Crohn’s disease and started their treatment, regular monitoring and follow-ups are crucial.

A person will likely need periodic blood testing, including tests that check for infection, inflammation, liver enzymes, and electrolyte status.

People with Crohn’s disease have an increased risk of colon cancer. Therefore, doctors will carry out surveillance colonoscopy examinations regularly. During a colonoscopy, a doctor will perform a biopsy, taking samples of tissue to check for dysplasia or cancer.

A doctor might also use chromoendoscopy during a colonoscopy. Chromoendoscopy involves spraying a liquid blue dye over the surface of the colon. Collections of the blue dye help the doctor identify potential precancerous areas in the intestine.

People with Crohn’s disease may have an increased risk of other types of cancer and infection as a result of taking immunosuppressant medications, which are drugs that reduce immune system activity. Therefore, it is important for these individuals to stay up to date with cancer screenings and immunizations.

The following symptoms are common among people with Crohn’s disease:

  • ongoing diarrhea
  • abdominal cramping
  • an urgent need to use the bathroom
  • bloody stools
  • alternating constipation and diarrhea

These symptoms occur because of the inflammation that Crohn’s disease causes. However, it is easy to confuse these symptoms with those of other conditions.

Learn more about the differences between the symptoms of Crohn’s disease and an upset stomach.

If these symptoms are persistent, a person should see their doctor for an evaluation.

Crohn’s disease can also cause symptoms that occur outside of the GI tract. These symptoms include:

Crohn’s disease is a chronic inflammatory bowel disease that causes abdominal cramping, diarrhea, and GI bleeding.

Doctors diagnose Crohn’s disease by performing several different tests, which can include blood testing, stool testing, imaging, and endoscopy.

People with Crohn’s disease require regular medical follow-ups to monitor the effectiveness of their treatment plan.

Anyone who is concerned about Crohn’s disease should speak with their doctor.