Taken directly from Wikipedia.  Rome Process for Diagnosing IBS

Physicians rely on a variety of procedures and laboratory tests to confirm a diagnosis. The cardinal requirement for the diagnosis of IBS is abdominal pain. The Rome II criteria are used to diagnose IBS after a careful examination of the patient's medical history and physical abdominal examination which looks for any 'red flag' symptoms. More recently, the Rome III criteria, incorporating some changes over the previous set of criteria, have been issued. The Rome II and III efforts have integrated pediatric components in their set of criteria.

According to the Rome II committees and the Functional Brain Gut Research Group, IBS can be diagnosed based on at least 12 weeks, which need not be consecutive, of the preceding 12 months there was abdominal discomfort or pain that had two out of three of these features:

Relieved with defecation; and/or

Onset associated with a change in frequency of stool; and/or

Onset associated with a change in form (appearance) of stool.

Symptoms that cumulatively support the diagnosis of IBS:

Abnormal stool frequency (for research purposes, "abnormal" may be defined as greater than three bowel movements per day and fewer than three bowel movements per week);

Abnormal stool form (lumpy/hard or loose/watery stool);

Abnormal stool passage (straining, urgency, or feeling of incomplete evacuation);

Bloating or feeling of abdominal distention.

Supportive symptoms of IBS:

A) Fewer than three bowel movements a week

B) More than three bowel movements a day

C) Hard or lumpy stools

D) Loose (mushy) or watery stools

E) Straining during a bowel movement

F) Urgency (having to rush to have a bowel movement)

G) Feeling of incomplete bowel movement

H) Passing mucus (white material) during a bowel movement

I) Abdominal fullness, bloating, or swelling

Diarrhea-predominant: At least 1 of B, D, F and none of A, C, E; or at least 2 of B, D, F and one of A or E.

Constipation-predominant: At least 1 of A, C, E and none of B, D, F; or at least 2 of A, C, E and one of B, D, F.

Red flag symptoms which are not typical of IBS:

Pain that awakens/interferes with sleep

Diarrhea that awakens/interferes with sleep

Blood in the stool (visible or occult)

Weight loss

Fever

Abnormal physical examination

An update to these criteria was issued at the Rome III conference and published in May 2006.[3] The validity of subtypes is called into question:

The validity and stability of such subtypes over time is unknown and should be the subject of future research.

Because of the characteristic symptom instability, we prefer the terms IBS with constipation and IBS with diarrhea instead of constipation- and diarrhea-predominant IBS. In this categorical system, many people whose features place them close to a subtype boundary change pattern without a major change in pathophysiology. Moreover, the heterogeneity and variable natural history of IBS significantly limit clinical trials of motility-active drugs and drug therapy in practice.

In addition to meeting these positive criteria, patients have initial laboratory testing with a complete blood count, basic chemistry panel, and an erythrocyte sedimentation rate. Diagnostic accuracy for IBS is over 95% when Rome II criteria are met, history and physical exam do not suggest any other cause, and initial laboratory testing is negative.

In the past it was thought that the diagnosis of IBS relied on a diagnosis of exclusion; that is, if one cannot find a cause then IBS is the diagnosis. Currently the diagnosis of IBS relies on meeting Rome II inclusion criteria (updated by Rome III criteria) and excluding other illnesses based on history, physical exam, and laboratory testing. Although the Rome II and III criteria were not designed to be management guidelines, they are currently a "gold standard" for the diagnosis of IBS. Unfortunately, an IBS diagnosis in an adult patient is still only useful as a tool to rule out more serious problems unless further investigation is employed to discern an addressable condition.


Diagnosing IBS

The "Rome process" is an international effort to create scientific data to help in the diagnosis and treatment of functional gastrointestinal disorders, (FGIDs), such as irritable bowel syndrome, functional dyspepsia and rumination syndrome. The Rome Diagnostic Criteria are set forth by the Rome Foundation, a not for profit 501 organization, under the professional management of Hilliard Associates based in Raleigh, North Carolina.

There were systematic approaches that attempted to classify the then hazy area of functional gastrointestinal disorders as early as 1962 when Chaudhary and Truelove published a retrospective review of IBS patients at Oxford, England. Later on, the "Manning Criteria" for irritable bowel syndrome were derived from a paper published in 1978 by Manning and colleagues. This seminal classification started a new era and from then on, scientific work on functional gastrointestinal disorders proceeded with increased enthusiasm.

The Rome criteria have been evolving from the first set of criteria issued in 1989 (The Rome Guidelines for IBS) through the Rome Classification System for FGIDs (1990), or Rome-1, the Rome I Criteria for IBS (1992) and the FGIDs (1994), the Rome II Criteria for IBS (1999) and the FGIDs (1999) to the recent Rome III Criteria (2006). "Rome II" and "Rome III" incorporated pediatric criteria to the consensus.

What is The Rome Criteria

The Rome Criteria

The Rome Criteria