Rome IV Diagnostic Criteria for Irritable Bowel Syndrome (IBS)
The Rome IV criteria for IBS require recurrent abdominal pain at least 1 day per week in the last 3 months, with symptom onset at least 6 months before diagnosis, associated with two or more of: pain related to defecation, change in stool frequency, or change in stool form. 1
Evolution of IBS Diagnostic Criteria
The Manning criteria (1978) established six key symptoms for IBS diagnosis: abdominal pain relieved by defecation, looser stools with onset of pain, more frequent stools with onset of pain, abdominal distension, passage of mucus, and sensation of incomplete evacuation 2
The Rome I criteria (1990s) required at least three months of recurrent symptoms of abdominal pain/discomfort relieved with defecation or associated with change in stool frequency/consistency, plus two or more supportive symptoms (altered stool frequency/form/passage, mucus passage, bloating) 2
The Rome II criteria (late 1990s) required 12 weeks of abdominal discomfort/pain in the past 12 months with two of three features: relief with defecation, onset associated with change in stool frequency, or onset associated with change in stool consistency 2
The Rome III criteria modified the timeframe, requiring symptoms to have originated 6 months prior to diagnosis and been active for the past 3 months 1
The Rome IV criteria (current standard) made two significant changes: removing "discomfort" (keeping only "pain") and increasing the required frequency to at least 1 day per week (from 3 days per month in Rome III) 1, 3
Current Rome IV Diagnostic Criteria in Detail
Recurrent abdominal pain, on average, at least 1 day per week in the last 3 months, associated with two or more of the following:
- Related to defecation (improvement or worsening) 2, 1
- Associated with a change in frequency of stool 2, 1
- Associated with a change in form (appearance) of stool 2, 1
These criteria must be fulfilled for the last 3 months with symptom onset at least 6 months before diagnosis 2, 1
IBS Subtypes Based on Rome IV
IBS is further classified into subtypes based on predominant stool pattern:
- IBS with constipation (IBS-C) 1
- IBS with diarrhea (IBS-D) 1
- Mixed IBS (IBS-M) 1
- Unsubtyped IBS (IBS-U) 1
Clinical Approach to Diagnosis
Perform a thorough evaluation for "red flags" that warrant further investigation, including weight loss, rectal bleeding, anemia, and nocturnal symptoms 2, 1
Consider supportive clinical features: female predominance, age <45 years with symptoms >2 years, and history of frequent healthcare visits for non-gastrointestinal complaints 2
Limit diagnostic testing to stool Hemoccult and complete blood count as baseline 1
Consider sigmoidoscopy if colonic symptoms are present, especially in patients over 45 years or with a family history of colon cancer 2
Additional investigations (thyroid function, celiac antibodies, stool microscopy) should be performed at the first visit if indicated, avoiding repetitive testing 2
Important Caveats and Considerations
The Rome IV criteria are more restrictive than Rome III, resulting in lower prevalence estimates (4.1% vs 10.1%) 1, 4
Up to 50% of patients who met Rome III criteria may not meet Rome IV criteria due to the stricter pain frequency requirement 1, 5
The Rome IV criteria have better specificity (82.9%) but may miss some IBS cases due to reduced sensitivity compared to Rome III 4
Recent research suggests that modifying the Rome IV criteria by relaxing the frequency of abdominal pain to 3 days per month may improve diagnostic performance 6
Once a functional diagnosis is established, the incidence of new non-functional diagnoses is extremely low 2
Symptoms often fluctuate over time, and subtype classification may change 1
Functional disorders frequently overlap with each other, complicating diagnosis 1