🌀 IBS Diagnostic Rome IV Criteria Simulator

Recurrent Abdominal Pain Assessment

Diagnosis starts with characterizing recurrent abdominal pain.

• ~4%: Global IBS prevalence (Rome IV strict criteria)
• 2:1: Female-to-male ratio (higher symptom burden)
• <50: Typical onset age (years old)
• ~12%: Primary care GI visits (attributed to IBS)

What counts as recurrent pain

Pain must be a repeating pattern, not a one-off episode.

Rome IV replaces Rome III

Rome IV dropped "discomfort" and tightened frequency wording.

Why criteria-based diagnosis matters

Structured criteria avoid unnecessary invasive testing.

Rome IV enables positive diagnosis, not just exclusion.

The Frequency Criterion — At Least 1 Day per Week

Pain frequency and duration are checked against the Rome IV bar.

• 1 day/wk: Minimum frequency (average over interval)
• 3 months: Required duration (symptoms active)
• 6 months: Onset lookback (before diagnosis)
• Pain diary: Assessment tool (or recall interview)

The 1-day-per-week bar

Rome IV lowered the bar from Rome III's 3 days/month.

The 3-month / 6-month rule

Active 3 months, with onset at least 6 months prior.

Why frequency alone is not enough

Frequency confirms chronicity, not the IBS mechanism.

Frequency criterion alone cannot diagnose IBS.

Pain Associated with Defecation or Stool Change

Pain must link to defecation, stool frequency, or stool form.

• 3: Sub-criteria (defecation, frequency, form)
• 7: Bristol scale types (stool form categories)
• ≥1 of 3: Required linked features (to satisfy criterion)
• 4: IBS subtypes (IBS-C, IBS-D, IBS-M, IBS-U)

Three stool-related sub-criteria

Related to defecation, or a change in frequency or form.

Bristol Stool Form Scale

Types 1–2 signal constipation, 6–7 signal diarrhea.

Subtyping after diagnosis

Predominant stool pattern sets the IBS subtype.

Only one of the three sub-criteria needs to be present.

Both Criteria Converge

Frequency and stool-association checkmarks both light up.

• 2 of 2: Criteria required (frequency + stool link)
• AND: Logical operator (not either/or)
• High: Diagnostic confidence (when both satisfied)
• 1: Remaining step (alarm feature screen)

AND logic, not OR

Both branches must be satisfied simultaneously.

Convergence at the diagnostic node

Two checkmarks feed one confirmation icon.

What still needs checking

Alarm features must be excluded before finalizing.

Meeting both criteria alone is not yet a diagnosis.

Rome IV Criteria Met — IBS Diagnosis Confirmed

Alarm features are screened out and the diagnosis is confirmed.

• 6+: Alarm features screened (red-flag symptoms)
• Excluded: Bleeding, weight loss (if present, refer further)
• ~97%: Diagnostic accuracy (when alarms absent)
• Many: Unnecessary colonoscopies avoided (via criteria-first approach)

Alarm feature exclusion

Bleeding, anemia, weight loss, or family history flag concern.

Positive diagnosis, not exclusion

Rome IV confirms IBS without requiring endless testing.

Rome IV criteria met plus no alarms equals confirmed IBS.

After diagnosis

Subtype guides diet, medication, and follow-up plans.