Magnetically Controlled Capsule Endoscopy First vs. Standard Algorithm in Patients With Melena

Inclusion Criteria: * Age ≥ 18 years * Presenting to the outpatient department or emergency department with melena (without hematemesis) within the previous 48 hours * Hemodynamically stable (blood pressure \> 100/60 mmHg and heart rate \< 100 bpm) at presentation * No endoscopy performed after the new onset of melena Exclusion Criteria: * Presenting with hematochezia and/or hematemesis within the previous 48 hours of presentation * Hemodynamically stable after initial volume resuscitation * Drop of hemoglobin level ≥ 2 g/dL/day, and/or need of transfusion ≥ 2 units of packed red blood cells per day * Contraindications of CE (e.g. dysphagia, Zenker's diverticulum, esophageal stricture, known or suspected gastric or small bowel obstruction or perforation, gastroparesis, history of upper gastrointestinal surgery or abdominal surgery altering gastrointestinal anatomy, or post-abdominal radiation, etc.) * Presence of internal cardiac defibrillator (ICD), pacemaker and/or other implanted electronic devices (cochlea, drug infusion pump, nerve stimulator, etc.) or magnetic metal foreign bodies; possibility of requiring an MRI examination prior to capsule excretion * Patients who cannot undergo surgery in the event of capsule retention * Pregnant and/or lactating women * Patients with altered mental status (such as hepatic encephalopathy) * Patients moribund from terminal malignant diseases or other end-stage illnesses with a limited life expectancy * Unable to consent