What are the indications for referring a patient with chronic diarrhoea to a gastroenterologist?

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

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Referral to a gastroenterologist for chronic diarrhoea in adults is indicated in several situations, particularly when red flag symptoms are present or the diagnosis remains uncertain after initial primary care assessment .

Urgent Suspected Cancer Pathway Referral ,:
  • A patient should be referred using a suspected cancer pathway if they have a positive quantitative faecal immunochemical test (FIT) and are aged 40 and over with unexplained weight loss and abdominal pain, or aged 50 and over with unexplained rectal bleeding, or aged 60 and over with iron deficiency anaemia or changes in their bowel habit, or tests show occult blood in their faeces .
  • Consider a suspected cancer pathway referral if adults have a positive FIT and a rectal or abdominal mass .
  • Adults aged under 50 with rectal bleeding and any of the following unexplained symptoms or findings should also be considered for a suspected cancer pathway referral: abdominal pain, change in bowel habits, weight loss, or iron-deficiency anaemia .
Other Red Flag Indicators for Specialist Referral ,:
  • Unexplained weight loss .
  • Unexplained rectal bleeding or persistent blood in the stool .
  • Abdominal or rectal mass .
  • Severe abdominal pain .
  • Iron deficiency anaemia .
  • Raised inflammatory markers, which may indicate inflammatory bowel disease ,.
  • Nocturnal or continuous diarrhoea, suggesting an organic rather than functional disorder .
  • Fever, tachycardia, hypotension, or dehydration .
  • Features suggestive of an underlying cause such as chronic fatty diarrhoea (indicating fat maldigestion or malabsorption, for example, pancreatic insufficiency or coeliac disease) .
  • A family history of coeliac disease or inflammatory bowel disease .
  • Immunocompromised status, considering opportunistic infection .
  • Features of systemic disease like thyrotoxicosis, diabetes, or adrenal insufficiency .
  • Rashes such as pyoderma gangrenosum or erythema nodosum (in inflammatory bowel disease) or dermatitis herpetiformis (in coeliac disease) .
Uncertain Diagnosis :
  • Referral is indicated if the diagnosis remains uncertain after a primary care assessment, especially if infection and other common causes of acute diarrhoea have been excluded and a chronic cause is suspected .
Consideration for Specialist Assessment :
  • Faecal calprotectin testing can help differentiate between irritable bowel syndrome and inflammatory bowel disease in people under 40 years if specialist assessment is being considered and cancer is not suspected .

Related Knowledge Topics

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