Occult gastrointestinal bleeding. General overview and approach.

Occult gastrointestinal bleeding is most commonly defined as an acute or chronic loss of blood, the source of which has not been identified after gastroscopy, colonoscopy, and upper gastrointestinal series have been performed. As the title suggests, this article provides a general overview of this disorder. Specific topics discussed include etiology, diagnostic procedures, laboratory studies, radiologic procedures, radionuclide studies, angiography, and endoscopy.