Getting a correct diagnosis of inflammatory bowel disease (IBD) often involves several steps, such as endoscopy and imaging tests. Each carries its own criteria for diagnosis and possible risks.

IBD diagnostic processShare on Pinterest
Designed by: Jason Hoffman

IBD may include ulcerative colitis and Crohn’s disease. Both conditions cause inflammation and damage to the intestines.

The symptoms of IBD can also mimic other types of intestinal conditions. Several diagnostic tests help confirm a diagnosis and determine which form of IBD a person has. A doctor may order different tests depending on the symptoms present.

The article below explains the diagnostic tests for IBD, including how they work and their risks.

A stool test involves using a stool sample to check for certain factors that may rule out IBD or help make a diagnosis.

How it works

A lab technician will analyze the sample to check for blood, pathogens, and signs of inflammation.

Criteria for diagnosis

The presence of certain biomarkers, including calprotectin and lactoferrin, may indicate inflammation in the intestines.

According to the University of Iowa’s pathology lab, a borderline elevated calprotectin level is 50–120 micrograms per gram (ug/g), while an elevated level is 121 ug/g or greater.

However, a 2017 article in the journal Gastroenterology and Hepatology suggests there are no fixed rules for evaluating calprotectin values. It states that levels up to 100 ug/g may be “normal” values for some kits, and doctors are improving in judging test results in relation to the symptoms of individual patients.

Technicians will also analyze stool samples for the presence of any parasites, bacteria, or viruses that may cause symptoms similar to IBD.

What to expect from the results

Doctors may recommend additional testing if a stool test indicates that inflammation is present.

Possible risks

There are no risks involved in providing a stool sample. Because this test is noninvasive, it is often one of the first that doctors order in diagnosing IBD.

A few different types of endoscopies are available that help doctors diagnose IBD. The option they select may depend on the symptoms present.

How it works

An endoscopy involves inserting a small camera attached to a tube inside the intestinal tract. The test allows doctors to see inflammation in the intestines.

Types of endoscopies include the following:

  • Colonoscopy: This test allows doctors to examine the large intestine by inserting a scope into the anus.
  • Sigmoidoscopy: A sigmoidoscopy helps doctors see the left side of the colon and rectum through a scope they insert into the anus.
  • Upper gastrointestinal (GI) endoscopy: This procedure allows doctors to view the upper GI tract through a tube they insert through the mouth.
  • Video capsule endoscopy: A video capsule endoscopy involves the patient swallowing a capsule that contains a small camera that takes pictures of the small intestines. After the test, the patient passes the camera through a bowel movement.

Criteria for diagnosis

Someone with IBD likely has inflammatory changes that doctors can see using endoscopy. The type of changes may depend on the form of IBD present. Possible indications include:

  • deep inflammation in the mucosa, the membrane lining the digestive tract, or submucosa
  • ulcers in the intestinal tissue
  • small tears in the tissue

What to expect from the results

Endoscopy results help doctors determine the presence of inflammatory signs of IBD. They may also assist in identifying the extent of the condition.

If doctors rule out other conditions, an endoscopy may be the best step in diagnosing IBD.

Possible risks

Possible risks of endoscopy may depend on the specific type of procedure performed. General risks include:

Imaging tests create a picture of the intestines to check for structural changes and other causes of intestinal symptoms.

How it works

Usually, imaging tests involved in diagnosing IBD include a barium contrast study. This is when a person drinks a contrast material containing barium before a technician takes a series of X-rays or CT scans. The barium helps increase the visibility of the organs.

Criteria for diagnosis

The images may show areas of inflammation that, along with other tests, confirm a diagnosis of IBD.

What to expect from the results

Imaging test results help doctors identify problems, such as intestinal blockages, scarring, and swelling of the intestines.

Possible risks

Few risks exist for imaging tests. However, some people may feel nauseous or become constipated due to the barium they have to consume.

In rare cases, an adverse reaction to barium can also occur.

Doctors may also use other methods to help identify IBD. The first step may involve a medical history.

Usually, doctors ask questions related to the following:

  • symptoms present
  • family medical history
  • bowel habits

Doctors generally also perform a physical exam, which often includes checking the following:

The doctor will usually check the abdomen for pain and tenderness and listen to abdominal sounds through a stethoscope.

Medical professionals will generally also order blood tests to look for signs of infection and anemia, which could indicate bleeding in the colon or rectum.

Diagnostic tests for IBD may include a combination of noninvasive and invasive tests.

Typically, doctors start with a medical history and physical exam. Based on symptoms, they may suggest some form of endoscopy to view the intestines. Imaging tests may also help detect changes in the intestines that can indicate the presence of IBD and the type a person has.