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Irritable Bowel Syndrome Diagnosis

There are many diseases which can easily be confused for IBS. Always consult your physician for a proper diagnosis of your symptoms. This diagnosis criteria is not intended for you to diagnosis yourself. Only your doctor can make that diagnosis.

In 1978 Manning et al., found, from questionnaire data, that IBS sufferers reported four common symptoms. The Manning Criteria was established to distinguish organic causes for symptoms from those of IBS. In 1992 the Rome I Criteria was established by a multinational committee of specialists, which further refined the Manning Criteria. In 1998 the Rome Working Team proposed changes to the definition and diagnostic criteria for IBS to reflect new research data, and to improve clarity. They produced the Rome II Criteria. In 2006 this was further defined by the expanded Rome Working Team into what is now known as the Rome III Criteria.

The diagnosis of Irritable Bowel Syndrome has relied on a diagnosis of exclusion. Because the symptoms of IBS share the symptoms of so many other intestinal illnesses, it sometimes takes years before a correct diagnosis is made to exclude the obvious, and not so obvious, conditions which present symptoms similar to IBS.

Physicians rely on a variety of procedures and laboratory tests to confirm a diagnosis. The Rome II Criteria, however now defines markers which allows professionals to diagnose IBS after a careful examination of a sufferers medical history and physical abdominal examination which looks for any 'red flag' symptoms.

Red Flag symptoms which are NOT typical of IBS:


The diagnostic criteria of Irritable Bowel Syndrome always presumes the absence of a structural or biochemical explanation for the symptoms and is made only by your health care professional. Using the Rome II definition, Irritable Bowel Syndrome can be diagnosed based on at least 12 weeks, which need not be consecutive, in the preceding 12 months of abdominal discomfort or pain that has two out of three features:

1. Relieved with defecation; and/or
2. Onset associated with a change in frequency of stool; and/or
3. Onset associated with a change in form (appearance) of stool.

Symptoms that Cumulatively Support the Diagnosis of IBS:

  • Abnormal stool frequency (may be defined as greater than 3 bowel movements per day and less than 3 bowel movements per week);
  • Abnormal stool form (lumpy/hard or loose/watery stool);
  • Abnormal stool passage (straining, urgency, or feeling of incomplete evacuation);
  • Passage of mucus;
  • Bloating or feeling of abdominal distension.

Supportive Symptoms of IBS:

1. Fewer than three bowel movements a week
2. More than three bowel movements a day
3. Hard or lumpy stools
4. Loose (mushy) or watery stools
5. Straining during a bowel movement
6. Urgency (having to rush to have a bowel movement)
7. Feeling of incomplete bowel movement
8. Passing mucus (white material) during a bowel movement
9. Abdominal fullness, bloating, or swelling

Diarrhea-predominant: 1 or more of 2, 4, 6 and none of 1, 3, or 5; or: 2 or more of 2, 4, or 6 and one of 1 or 5. (3. Hard or lumpy stools do not qualify.)
Constipation-predominant: 1 or more of 1, 3, 5 and none of 2, 4, or 6;or: 2 or more of 1, 3, or 5 and one of 2, 4 or 6.
© Rome II Criteria, Degnon Assoc. 2000
Source: Rome II, Degnon Associates ISBN 0965681729