What are the key diagnostic criteria for Irritable Bowel Syndrome (IBS) according to the Rome IV guidelines?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

The key diagnostic criteria for Irritable Bowel Syndrome (IBS) according to the Rome IV guidelines are:

  • Presence of abdominal pain or discomfort that has been experienced for at least 6 months.
  • The abdominal pain or discomfort should be either relieved by defaecation or associated with a change in bowel frequency or stool form.
  • In addition to abdominal pain or discomfort, at least two of the following symptoms must be present:
    • Altered stool passage, such as straining, urgency, or a feeling of incomplete evacuation.
    • Abdominal bloating, distension, tension, or hardness.
    • Symptoms that worsen after eating.
    • Passage of mucus in the stool.
  • Other supporting features may include lethargy, nausea, backache, and bladder symptoms, but these are not required for diagnosis.

These criteria help distinguish IBS from other conditions and guide the clinical diagnosis process.

Note: Diagnosis should be considered only after excluding 'red flag' symptoms and other organic diseases through appropriate clinical assessment and investigations.

All information is based on the NICE guideline CG61 on Irritable bowel syndrome in adults: diagnosis and management.

Educational content only. Always verify information and use clinical judgement.