How to Get an Ulcerative Colitis Diagnosis

Medically reviewed by Robert Burakoff, MD

Ulcerative colitis is an immune-mediated condition that causes inflammation. It primarily affects the large intestine and the rectum, causing ulcers in the intestinal lining, which may bleed. It can also cause other complications outside of the digestive system. It is one form of a group of conditions called inflammatory bowel disease (IBD).

The diagnostic process for ulcerative colitis may involve several types of tests, some of which are invasive. The process of receiving a diagnosis of this lifelong condition can be overwhelming.

This article will cover the various tests that might be used when looking for the cause of digestive symptoms that may indicate ulcerative colitis.

How Do Doctors Diagnose Ulcerative Colitis?

The diagnosis of ulcerative colitis may take several steps. When the signs and symptoms seem to point towards this condition, a person is usually referred to a gastroenterologist. A gastroenterologist is a specialized healthcare provider who treats digestive system disorders.

Ulcerative colitis is a common condition, especially in Europe, the United States, Canada, and Australia. It may be uncommon or rare in other areas of the world.

Conditions that cause similar symptoms will be ruled out during the diagnostic process. The testing might start with less invasive labs (such as stool and blood tests) before moving on to endoscopy.

Usually, ulcerative colitis is diagnosed with a colonoscopy or a sigmoidoscopy. In these procedures, the healthcare provider can see inside the colon and take samples of tissue for testing. Knowing how much inflammation is present and how much of the colon is affected is important in making treatment decisions.

Initial Testing and Evaluation for Ulcerative Colitis

Symptoms of diarrhea, bloody stools, weight loss, abdominal cramps or pain, and an urgent need to use the toilet may be what leads a person to see a healthcare provider. The first steps when seeing a provider is to give a detailed medical history and getting a physical exam.

A medical history includes answering questions such as when the symptoms started, how often there is diarrhea, where any pain is located, and if there is blood in the stool. It’s helpful for the person to bring up all the symptoms they are experiencing, even those outside the digestive system (such as losing weight or being fatigued).

The physical exam can include a healthcare provider checking vitals (blood pressure, temperature). There may also be an exam of the abdomen to see if there are any tender areas or anything else that feels unusual.

A digital rectal exam may also be done to look for problems in the rectum. This exam is done by a healthcare provider inserting a gloved, lubricated finger into the rectum. It will be as brief as possible, and the healthcare provider will feel for anything out of the ordinary, such as hemorrhoids.

Related: How to Find the Best Doctor for Ulcerative Colitis

Lab Tests: Blood and Stool

The results of lab tests aren’t used to diagnose ulcerative colitis by themselves. However, these tests can rule out other conditions that have symptoms similar to ulcerative colitis. In addition, they can give more information about the effects that ulcerative colitis may have on the body (such as causing inflammation and blood loss).

Blood Tests

The workup for ulcerative colitis may involve many different blood tests. This can include:

• Albumin level, which may be decreased

• C-reactive protein level, which may be increased

• Erythrocyte sedimentation rate (ESR or sed rate), which may be increased

• Hemoglobin level, which may be decreased

• Platelet count, which may be increased

• White blood cell count, which may be increased

These tests might also be done every so often to monitor the progress of ulcerative colitis, along with other tests, as ordered by a healthcare provider. Because ulcerative colitis affects people differently, other blood tests may be done.

Stool Tests

Stool tests are used in the diagnostic process and during management to keep tabs on the state of the inflammation. These tests alone aren’t used to diagnose ulcerative colitis; instead, they support the diagnosis and determine the severity of the condition.

A stool sample is collected and sent for testing for an infection or other signs of IBD.

During diagnosis, a stool test might be used to rule out an infection. Some infections can cause symptoms that are similar to ulcerative colitis. In addition, people with IBD may be at higher risk for having certain bowel infections, such as Clostridioides difficile (formerly Clostridium difficile) (C. diff) or cytomegalovirus.

A fecal calprotectin test may also be done. Calprotectin is a type of protein found in higher amounts in the stool of people who live with IBD. Calprotectin levels can be higher in IBD but also in other digestive conditions, so it’s not used by itself to make a diagnosis.

Endoscopic Procedures

Endoscopic procedures are used to look inside the digestive system. There are several different types. A healthcare provider may order one or more of these tests during the diagnostic process to see the large intestine or other parts of the digestive system.

Colonoscopy

A colonoscopy is used to see the inside of the large intestine. Because ulcerative colitis affects this part of the digestive system, this test can give important information. It may be used to diagnose ulcerative colitis when a healthcare provider sees signs of the condition (such as ulcers) in the colon.

How a Colonoscopy Is Performed

A colonoscopy is done by passing a colonoscope (a long, thin, flexible tube with a light and camera on the end) through the anus and up through the colon. This test involves preparation to clean all the stool out of the colon on the day before the procedure.

It is usually done under anesthesia, so people will need to take the day off work and school and be driven home by a responsible adult.

During the course of a colonoscopy, biopsies (small pieces of tissue) will be taken from various parts of the colon and sent to a lab for testing. The results of these tests can help in making the diagnosis of ulcerative colitis.

A colonoscopy may also be used to determine the type of ulcerative colitis you have by determining how far the inflammation extends up into the large intestine. The different forms include:

• Ulcerative proctitis: Inflammation only in the rectum

• Proctosigmoiditis: Inflammation in the rectum and sigmoid colon

• Left-sided colitis: Inflammation in the rectum, sigmoid colon, and descending colon

• Pancolitis: Inflammation throughout the colon

Related: How Do I Know When Colonoscopy Prep Is Complete?

Sigmoidoscopy

A sigmoidoscopy is similar to a colonoscopy in that it involves inserting a special tool with a light and a camera on the end into the rectum. The difference is that this test is used to see just the rectum and the first section of the colon (the sigmoid colon).

This test may be done in the healthcare provider’s office without a prep or anesthesia. Some providers may ask people to prepare ahead of time with an enema or another method to clean out the rectum.

The test will be done as quickly as possible. People may feel discomfort if it’s not done using sedation. Talk over any concerns about the procedure, including discomfort or pain, with your healthcare provider beforehand.

Chromoendoscopy

People with ulcerative colitis may be at risk for changes in the tissue of the colon that could lead to colon cancer. The risk of cancer increases after having the disease for more than eight years. Chromoendoscopy is the use of a blue dye during a colonoscopy to mark areas of the colon that look like they may be undergoing precancerous changes.

Related: The Different Types of Endoscopy Procedures

Biopsy

Biopsies that are taken from the colon can help in diagnosing ulcerative colitis. They may also be used to rule out other diseases and conditions.

During a colonoscopy or a sigmoidoscopy, a healthcare provider will take a number of biopsies from different parts of the intestine. These will be sent to a pathologist (a physician who studies body fluids, tissues, or organs). The pathologist will examine the tissue under a microscope and with other methods.

Imaging Procedures

Other tests might be used during the diagnosis process. If ulcerative colitis is diagnosed with a colonoscopy, and there are no symptoms in the upper digestive tract, these imaging tests might not be used.

X-Ray

An X-ray may be used while looking for a diagnosis. It can not be used to diagnose ulcerative colitis. However, it is a quick, easily available test that can rule out other reasons for the symptoms.

CT scan

A computed tomography (CT) scan of the small intestine may be used if there are symptoms that could be from that area. In this test, X-rays are used to create an image of the structures inside the abdomen. This test can show if there are abnormalities or problems with the upper digestive system.

Contrast solution may be given with an intravenous (IV) line or in a drink. It helps the structures of the abdomen show up better on the X-ray film.

CT Enterography

A computed tomography enterography can be used to see the walls of the intestine. This test uses radiation, but it is less than that of a traditional X-ray. In ulcerative colitis, the wall of the large intestine may become thickened. A thickened wall might be seen on a CT enterography.

This test may be done using contrast so the healthcare providers who look at the images can better see the organs in the digestive system.

MR Enterography

A magnetic resonance (MR) enterography is a test that doesn’t involve radiation. It may be used to create an image of the organs in the abdomen. This test may be done with contrast fluid via an IV and/or with a drink so the internal structures show up better on the images.

This test isn’t used to diagnose ulcerative colitis. However, it can give better images and more information than an X-ray or a CT enterography. It may be used to rule out other reasons for symptoms or to look for abnormalities like narrowed areas in the intestine.

Related: The Risks of Untreated Ulcerative Colitis

Summary

Diagnosing ulcerative colitis will involve several different types of tests or procedures. Ulcerative colitis is usually diagnosed with a colonoscopy where biopsies are taken. Other tests might be used to rule out different reasons for symptoms or to see if there is something going on outside of the large intestine.

Because ulcerative colitis affects everyone differently, in some cases, diagnosis may take some time. This condition requires management and treatment over a lifetime, so many tests that are used during diagnosis may also be done again on a regularly scheduled, ongoing basis.

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