IBS Diagnosis and Tests

How Is IBS Diagnosed?

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If you think you might have irritable bowel syndrome (IBS), learning how doctors come up with an IBS diagnosis will help to reassure you that your doctor is leading you on a proper course.

What Kind of Doctor Should I See?

If you are experiencing recurrent symptoms of abdominal pain, diarrhea and/or constipation, it is highly recommended that you make an appointment with your primary care physician. While you are waiting for your appointment, it would be helpful to start to keep a simple symptom diary.

Your physician is likely to run some blood work and test for blood in the stool. They should also test your blood to see if you have celiac disease. In the absence of any red-flag symptoms (e.g. rectal bleeding, fever, anemia), your primary care doctor may diagnose you as having IBS without any additional testing.

If your doctor believes that a more thorough investigation is necessary, you may be referred to a gastroenterologist. A gastroenterologist, commonly referred to as a GI, specializes in the diagnosis and treatment of digestive disorders. Gastroenterologists use their knowledge of the workings of the entire digestive system and their experience in the various disorders of the gastrointestinal system to come up with a comprehensive diagnosis and treatment plan.

IBS Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Man

What Tests am I Likely to Have?

In most cases, IBS can be diagnosed with a minimum of diagnostic procedures:

Are There Any Other Tests?

Should your symptom picture warrant it, your doctor might recommend one of these other common GI (gastrointestinal) procedures:

  • Colonoscopy: Scope of your entire large intestine. This test is routinely recommended to all individuals over the age of 50.
  • Sigmoidoscopy: Examination of the rectum and the lowest part of the colon, called the sigmoid colon.
  • Upper Endoscopy: Scope of your upper digestive tract, including your esophagus, stomach, and duodenum.
  • Barium Enema: X-ray of the large intestine with barium used for contrast.
  • Upper GI Series: X-rays of the upper digestive system with barium used for contrast.
  • Lactose Intolerance Testing
  • Stool test to rule out intestinal parasites

How Can My Doctor be Sure it is IBS?

Because IBS is considered a functional disorder, in that there is no visible disease process, physicians use a standard called the Rome III Criteria for diagnosing IBS. According to these criteria, IBS can only be diagnosed if symptoms have been present for at least six months. Symptoms must have been experienced on at least three days of at least three months. Specifically, symptoms must consist of recurrent abdominal pain or discomfort with two or more of the following:

  • Pain is relieved by a bowel movement
  • Onset of pain is related to a change in frequency of stool
  • Onset of pain is related to a change in the appearance of stool

If all other conditions have been ruled out and the conditions of the Rome III criteria are met, your doctor can confidently diagnose you as having IBS.

Will I Need Surgery?

Unless diagnostic testing reveals a more serious medical condition, patients with IBS do NOT need to undergo any surgical procedures. Research suggests that IBS patients are at higher risk to undergo gallbladder removal, appendectomy, hysterectomy and colon surgery, without necessarily receiving significant relief from their IBS symptoms. Due to the inherent risks of surgery, it is highly recommended that the IBS patient seek a second opinion before undergoing any type of surgery.

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Article Sources
  • Functional Bowel Disorders (2006) Longstreth, G.F., et.al. Gastroenterology, 130:1480-1491.
  • Medical Procedure Costs and Surgical Rates in Patients with Irritable Bowel Syndrome. (2007) Gamen, A. Digestive Health Matters, 16: 3-6.