Occult Gastrointestinal Bleeding

Occult gastrointestinal bleeding typically refers to bleeding that is not apparent to the patient. The potential for occult bleeding is emphasized by the finding that for melena to be produced consistently, 150 to 200 ml of blood must be present in the stomach.1 Moreover, patients with gastroduodenal blood loss of 100 ml per day may have stools that appear normal.2 Thus, occult bleeding is usually identified only by tests that detect fecal blood or, if bleeding is sufficient, when it becomes manifest as iron deficiency. Occult gastrointestinal bleeding can also refer to bleeding that is clinically evident but from an . . .