Ulcerative Colitis Diagnosis

Reviewed by: HU Medical Review Board | Last Reviewed: January 2016.

Ulcerative colitis is diagnosed based on symptoms, physical exam, laboratory tests, and endoscopy. The first goal is to determine what disease is causing the symptoms. Then your health care provider figures out how much of your intestine is involved and how severe the disease is. Finally, your health care provider will evaluate whether you have any complications related to ulcerative colitis.

History and Physical Exam

The most common symptoms of ulcerative colitis are:1,2

  • Rectal bleeding
  • Diarrhea
  • Abdominal pain
  • Urgency
  • Feeling of having an incomplete bowel movement

If you have these symptoms, your health care provider may suspect that you have ulcerative colitis. However, there are other diseases that could also cause these symptoms. Your provider will do additional tests to rule out conditions such as:2,3

Your provider may ask you questions such as:

  • How long have you had symptoms?
  • How often do you have symptoms?
  • Have you traveled recently?
  • What medications are you taking or have you taken recently?
  • Does anyone in your family have ulcerative colitis or Crohn’s disease?
  • Have you had any joint pain? Skin rashes? Eye irritation or inflammation?

Keeping a symptom diary may be helpful. You can record information such as when symptoms occur and how long they last. The diary is a good place to keep track of things that make your symptoms better or worse. Your health care provider will determine how severe your ulcerative colitis is based—in part—on how frequently you have diarrhea and whether blood is present.

Your provider may listen to your abdomen.3 He or she may feel for tenderness or pain and look for swelling. If your disease is severe, you may have a fever and fast heart rate.2 However, the physical exam is often normal for people with ulcerative colitis.

Blood tests

Ulcerative colitis cannot be diagnosed based on a blood test alone. However, some results point to ulcerative colitis. The results are used with information from your medical history to decide what diagnostic procedures are needed.

Tests for inflammation: Two common blood tests for inflammation are erythrocyte sedimentation rate and C-reactive protein levels. These tests may indicate that there is inflammation in the body, but they do not indicate the source. High platelet levels (called “thrombocytosis”) are common in inflammatory disease.2 Albumin, a protein in blood, may be low if there is inflammation. However, normal results do not rule out ulcerative colitis. You can have ulcerative colitis and normal test results.2

Tests for anemia: If you have anemia, your blood does not carry enough oxygen throughout your body.4Anemia is common in people with inflammatory bowel disease. Blood tests can be done to check how much hemoglobin you have, how big your red blood cells are, and what percentage of your blood is made of red blood cells.

Stool culture

Your health care provider may ask you to provide a stool sample. The sample may be tested for biomarkers called “calprotectin” and “lactoferrin.” If these biomarkers are found, there is inflammation in the intestine. However, it does not mean that the inflammation is necessarily caused by ulcerative colitis.5 The stool sample might also be tested to see if your symptoms are caused by bacteria or parasites.2

Endoscopy with biopsy

The most accurate way to diagnose ulcerative colitis is endoscopy with biopsy.3 Your doctor performs this procedure using a long, thin tube with a very small camera and light. The camera is inserted into the rectum. The camera lets your doctor look for signs of inflammation in your rectum and colon. One of the differences between ulcerative colitis and Crohn’s disease is the pattern of inflammation. People with Crohn’s disease can have patches of inflammation anywhere along the digestive tract. People with ulcerative colitis have inflammation in one continuous section of the colon and rectum.

The endoscopy also shows the doctor where the inflammation is located and how much of your intestine is affected. There are two kinds of endoscopic examinations:3

  • Colonoscopy: Examination of your rectum and entire colon.
  • Sigmoidoscopy: Examination of your rectum and lower colon.

The doctor may take a small tissue sample to examine under a microscope. This is called a biopsy.3 The biopsy confirms the diagnosis of ulcerative colitis.


Ulcerative colitis causes symptoms outside the intestine in about 10% and 30% of cases.6 The joints, skin, eyes, and liver are most commonly affected. Once you have been diagnosed with ulcerative colitis, your health care provider may ask questions about additional symptoms such as:

  • Joint pain.
  • Skin rashes or growths.
  • Eye pain or redness.
  • Blurry vision or sensitivity to light.

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