Occult gastrointestinal bleeding: locating the cause.
D000792:Angiography; D003106:Colon; D004724:Endoscopy; D005336:Fiber Optic Technology; D005767:Gastrointestinal Diseases / Q000150:complications / Q000175:diagnosis; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis* / Q000209:etiology; D005773:Gastroscopy; D006801:Humans; D007813:Laparotomy; D011877:Radionuclide Imaging