Inflammatory bowel disease (IBD) is an umbrella term used to describe disorders that cause chronic inflammation of the gastrointestinal (GI) tract.
The two types of IBD are:
- Ulcerative colitis (UC): affects the large intestine and rectum
- Crohn’s disease: can affect any part of the GI tract
The symptoms of IBD are also signs of other common conditions. This is why diagnosing IBD can sometimes be a challenge. Symptoms can include:
- abdominal pain
- diarrhea
- unexpected weight loss
- fatigue
- bloody stools
Several tests and exams are available to help doctors identify IBD and distinguish between the two types. An accurate diagnosis is the first step to successful treatment and management of your symptoms.
Diagnostic tests for Crohn’s disease
Doctors can use a variety of tests to diagnose Crohn’s disease.
First, a physician will likely ask about your medical history, and they’ll also perform a physical exam. Then, your doctor may order specific diagnostic tests to find out what’s causing your symptoms.
Lab tests
Some lab tests used to diagnose Crohn’s include:
- Blood tests. Blood tests can reveal your levels of red and white blood cells. If you have fewer red blood cells than normal, you could have anemia. This can indicate bleeding in the colon or rectum. A high white blood cell count means there could be inflammation or an infection somewhere in your body. Examining certain blood biomarkers, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), can also help doctors determine if there’s inflammation in your body .
- Stool tests. You’ll provide a sample of your poop in a small container. Analysts at a lab examine the sample to look for causes of digestive diseases. Analyzing certain stool proteins, such as calprotectin and lactoferrin, can alert doctors if you have gastrointestinal inflammation .
Scientists are currently studying whether certain markers found in a person’s blood, tissue, or other bodily fluids could help predict whether they will experience mild or severe symptoms of IBD.
But while these “prognostic” tests are currently available, they are still in their early stages of development and aren’t widely adopted.
Endoscopy
Endoscopy procedures are considered the most accurate way to diagnoseTrusted Source Crohn’s disease.
A healthcare professional might order one or more of the following types of endoscopy:
- Colonoscopy. A doctor uses an instrument called an endoscope (a thin tube with a light and camera attached) to look inside your colon and rectum. The doctor may also remove tissue samples (called a biopsy) to test for inflammation. This procedure is usually performed in a hospital or outpatient center. You will be given instructions on how to prep for a colonoscopy.
- Upper GI endoscopy and enteroscopy. With an upper GI endoscopy, a doctor gently directs an endoscope down your esophagus and into your stomach and duodenum (the first part of your small intestine) to look inside your upper digestive tract. They may also take biopsies. This procedure is usually performed at a hospital or outpatient center. For an enteroscopy, the doctor may use a special, longer instrument to examine the small intestine, too.
- Capsule endoscopy. With a capsule endoscopy, you’ll swallow a pill that contains a tiny camera. This lets the doctor see inside your digestive tract by recording and transmitting images to a small receiver that you wear. The capsule eventually leaves your body when you poop.
Imaging tests
Doctors may also recommend imaging tests to get a better look at what’s going on inside your body.
Some common imaging tests used for Crohn’s disease include:
- CT scan. A CT scan uses X-rays and computer technology to generate pictures of your digestive tract. You may be given a solution to drink, along with an injection of contrast medium, a special type of dye that makes it easier to see structures in your body. A CT machine takes X-rays as you lie on a table.
- Upper GI series. You’ll stand or sit in front of an X-ray machine and drink a chalky liquid called barium that makes your upper GI tract easier to view. Then, you’ll lie on an X-ray table while a doctor watches the barium move through your GI tract on an X-ray or fluoroscopy (a special type of X-ray that allows doctors to see your internal organs and their motion on a video monitor). You’ll be given specific details on how to prepare for this procedure.
- MRI scan. An MRI is a noninvasive test that uses magnets and radio waves to create cross-sectional images of your digestive tract. This type of test allows doctors to check hard-to-reach areas, like your small intestine, that are usually beyond the reach of endoscopy.
Diagnostic tests for ulcerative colitis (UC)
As with Crohn’s disease, a doctor might recommend a combination of tests to diagnose UC and determine the severity of your disease. They will usually start by asking about your family history and performing a physical exam.
Lab tests
Common lab tests used to help diagnose UC include:
- Blood tests. Doctors use a blood sample to look for signs of UC and complications, such as anemia. Your blood can also reveal signs of infection or other digestive issues.
- Stool tests. A stool sample can help doctors look for indicators of UC and rule out other conditions that could be causing your symptoms, such as an infection.
Endoscopy
Doctors use different endoscopy techniques to view and biopsy the large intestine. An endoscopy procedure helps diagnose UC and determine how much of the large intestine is affected.
The two most common types of endoscopy procedures used for UC include:
- Colonoscopy. During a colonoscopy, doctors use an endoscope to view the entire colon and rectum.
- Flexible sigmoidoscopy. A special type of flexible endoscope, called a sigmoidoscopy, is used to view the rectum and the lower part of the colon. Doctors may perform this test if your colon is very inflamed.
Imaging tests
Imaging tests, such as CT scans or X-rays, may be used to rule out other conditions or check for complications of UC.
What are the treatment options?
Once you’re diagnosed with Crohn’s disease or UC, work with a healthcare professional to get referred to a gastroenterologist who specializes in treating these diseases.
There isn’t a cure for IBD, but some therapies, procedures, and lifestyle changes can help you feel better and prevent complications. A gastroenterologist will likely start you on treatments and also recommend lifestyle and dietary changes to help ease your symptoms.
Your treatment will depend on the severity of your condition and other factors. Most people with IBD can live full, active lives once they know how to avoid symptoms and complications.
The takeaway
IBD is a complex disease that’s sometimes difficult to diagnose. If you develop any symptoms of IBD, it’s best to see your doctor to learn more about what could be causing your discomfort.
Several types of tests — including lab work, endoscopies, and imaging exams — can help your doctor determine if you have IBD and what type. You and your doctor can work together to determine the best type of treatment for your condition.
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Medically reviewed by Youssef (Joe) Soliman, MD — By Julie Marks on March 24, 2022
IBD Tests: Crohn’s, Ulcerative Colitis, and Next Steps (healthline.com)
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