Diagnosis of Irritable Bowel Syndrome

If you think you have Irritable Bowel Syndrome (IBS), seeing your doctor is the first step. IBS is generally diagnosed on the basis of a complete medical history that includes a careful description of symptoms and a physical examination.

There is no specific test for IBS, although diagnostic tests may be performed to rule out other diseases. These tests may include stool sample testing, blood tests, and x rays. Typically, a doctor will perform a sigmoidoscopy, or colonoscopy, which allows the doctor to look inside the colon. This is done by inserting a small, flexible tube with a camera on the end of it through the anus. The camera then transfers the images of your colon onto a large screen for the doctor to see better.

If your test results are negative, the doctor may diagnose IBS based on your symptoms, including how often you have had abdominal pain or discomfort during the past year, when the pain starts and stops in relation to bowel function, and how your bowel frequency and stool consistency have changed. Many doctors refer to a list of specific symptoms that must be present to make a diagnosis of IBS.

Symptoms include

1. Abdominal pain or discomfort for at least 12 weeks out of the previous 12 months. These 12 weeks do not have to be consecutive.

2. The abdominal pain or discomfort has two of the following three features:
  • It is relieved by having a bowel movement.
  • When it starts, there is a change in how often you have a bowel movement.
  • When it starts, there is a change in the form of the stool or the way it looks.

3. Certain symptoms must also be present, such as
  • a change in frequency of bowel movements
  • a change in appearance of bowel movements
  • feelings of uncontrollable urgency to have a bowel movement
  • difficulty or inability to pass stool
  • mucus in the stool
  • bloating
4. Bleeding, fever, weight loss, and persistent severe pain are not symptoms of IBS and may indicate other problems such as inflammation, or rarely, cancer.

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Source:
Topic Excerpted from: Irritable Bowel Syndrome. National Digestive Diseases Information Clearinghouse (NDDIC). National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). National Institutes of Health. NIH Publication No. 06–693: February 2006