Obscure GI Bleeding Investigation — RACP Adult Medicine MCQ

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ModerateGeneral Internal MedicineObscure GI Bleeding InvestigationRACP Adult Medicine

A 60-year-old man with iron deficiency anaemia (Hb 90 g/L, ferritin 8 µg/L) undergoes upper and lower GI endoscopy which are both normal. He has no coeliac disease. What additional investigation should be performed to identify the source of occult GI blood loss?

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Correct answer: B — Capsule endoscopy

When standard bidirectional endoscopy fails to identify a source of iron deficiency anaemia/occult GI bleeding (obscure GI bleeding), capsule endoscopy is the recommended next investigation. It visualises the entire small bowel (the only segment not reached by standard endoscopy) and can identify small bowel causes: angiodysplasia (most common in elderly), small bowel tumours, NSAID enteropathy, Crohn's disease, and Meckel's diverticulum. Capsule endoscopy has a diagnostic yield of 40–60% for obscure GI bleeding. CT enterography is an alternative but less sensitive for flat mucosal lesions.

Reference: eTG – 2025 – Gastrointestinal; BSG – 2024 – Capsule Endoscopy Guidelines