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How​​​​​​​​​​​​​​​ Is Ulcerative Colitis Diagnosed?

A healthcare provider may diagnose ulcerative colitis (UC) using the following:

A healthcare provider may perform a series of medical tests to rule out other bowel disorders, such as irritable bowel syndrome, Crohn's disease, or celiac disease, that may cause symptoms similar to those of UC.

Medical and Family History


Taking a medical and family history can help a healthcare provider diagnose UC and understand a patient's symptoms. The healthcare provider asks the patient about current and past medical conditions and medications.

Physical Exam


A physical exam may help diagnose UC. During a physical exam, a healthcare provider often

  • Checks for abdominal distension or swelling
  • Listens to sounds within the abdomen using a stethoscope
  • Taps on the abdomen to check for tenderness and pain

Lab Tests


A healthcare provider may order lab tests to help diagnose UC, including blood and stool tests.

Blood Tests

A blood test involves drawing blood at a healthcare provider's office or at a lab. A lab technologist analyzes the blood sample. A healthcare provider may use blood tests to look for

  • Anemia
  • Inflammation or infection somewhere in the body
  • Markers that show ongoing inflammation
  • Low albumin, or protein—common in patients with severe UC

Stool Tests

A stool test is the analysis of a sample of stool. The healthcare provider gives the patient a container for catching and storing the stool at home. The patient returns the sample to the healthcare provider or to a lab. A lab technologist analyzes the stool sample. Healthcare providers commonly order stool tests to rule out other causes of gastrointestinal (GI) diseases, such as infection.

Endoscopies of the Large Intestine


Endoscopies of the large intestine are the most accurate methods for diagnosing UC and ruling out other possible conditions, such as Crohn's disease, diverticular disease, or cancer. Endoscopies of the large intestine include

  • Colonoscopy
  • Flexible sigmoidoscopy

Colonoscopy

Colonoscopy is a test that uses a long, flexible, narrow tube with a light and tiny camera on one end, called a colonoscope or scope, to look inside the rectum and entire colon. In most cases, light anesthesia and pain medication help patients relax for the test. The medical staff monitor a patient's vital signs and try to make him or her as comfortable as possible. A nurse or technician places an intravenous (IV) needle in a vein in the patient's arm or hand to give the anesthesia.

For the test, the patient lies on a table or stretcher while the gastroenterologist inserts a colonoscope into the patient's anus and slowly guides it through the rectum and into the colon. The scope inflates the large intestine with air to give the gastroenterologist a better view. The camera sends a video image of the intestinal lining to a monitor, allowing the gastroenterologist to carefully examine the tissues lining the colon and rectum. The gastroenterologist may move the patient several times and adjust the scope for better viewing. Once the scope has reached the opening to the small intestine, the gastroenterologist slowly withdraws it and examines the lining of the colon and rectum again.

A colonoscopy can show irritated and swollen tissue, ulcers, and abnormal growths such as polyps—extra pieces of tissue that grow on the inner lining of the intestine. If the gastroenterologist suspects UC, he or she will biopsy the patient's colon and rectum. A biopsy is a procedure that involves taking small pieces of tissue for examination with a microscope.

The healthcare provider gives patients written bowel preparation instructions to follow at home before the test. The healthcare provider also gives patients information about how to care for themselves following the procedure.

Flexible Sigmoidoscopy

Flexible sigmoidoscopy is a test that uses a flexible, narrow tube with a light and tiny camera on one end, called a sigmoidoscope or scope, to look inside the rectum, the sigmoid colon, and sometimes the descending colon. In most cases, the patient does not need anesthesia.

For the test, the patient lies on a table or stretcher while the healthcare provider inserts the sigmoidoscope into the patient's anus and slowly guides it through the rectum, the sigmoid colon, and sometimes the descending colon. The scope inflates the large intestine with air to give the healthcare provider a better view. The camera sends a video image of the intestinal lining to a monitor, allowing the healthcare provider to examine the tissues lining the sigmoid colon and rectum. The healthcare provider may ask the patient to move several times and adjust the scope for better viewing. Once the scope reaches the end of the sigmoid colon, the healthcare provider slowly withdraws it while examining the lining of the colon and rectum again.

The healthcare provider looks for signs of bowel diseases and conditions such as irritated and swollen tissue, ulcers, and polyps. If the healthcare provider suspects UC, he or she will biopsy the patient's colon and rectum.

The healthcare provider gives patients written bowel preparation instructions to follow at home before the test. The healthcare provider also gives patients information about how to care for themselves following the procedure.

Reference:

The National Institute of Diabetes and Digestive and Kidney Diseases. Ulcerative colitis. https://www.niddk.nih.gov/health-information/digestive-diseases/ulcerative-colitis. Accessed February 14, 2018.