Review of small bowel capsule endoscopy for diagnosis of gastrointestinal bleeding

Capsule endoscopy (CE), introduced in 2001, is now a key tool for evaluating small-bowel bleeding, which accounts for 5% to 10% of gastrointestinal (GI) bleeding. As a minimally invasive modality, CE is recommended as the first-line test for both overt and obscure small-bowel bleeding, with a diagnostic yield of approximately 60%. It shows superior diagnostic yield compared to traditional modalities such as push enteroscopy and radiographic imaging. Current guidelines emphasize performing CE early, ideally within 48 hours of overt small bowel bleeding, to maximize diagnostic yield. In acute upper GI bleeding, CE shows comparable diagnostic accuracy to conventional upper endoscopy, making it an effective triage tool in emergency settings. Innovations such as magnetically controlled CE have further enhanced the evaluation of upper GI bleeding by improving maneuverability and visualization. For acute lower GI bleeding, pan-enteric CE provides comprehensive visualization of both the small bowel and colon and can detect small bowel lesions missed by colonoscopy, resulting in higher diagnostic yields. Technological advances including longer battery life, high-resolution imaging, artificial intelligence-assisted reading, and active capsule control continue to improve CE’s diagnostic performance across the GI tract. These improvements could facilitate full visualization of the entire GI tract through a single, noninvasive CE examination.