Some gastrointestinal (GI) problems (e.g., vomiting, diar- rhea, weight loss, anorexia, icterus, hepatomegaly, abnor- mal behavior associated with eating, abdominal pain) typically necessitate laboratory testing. On the other hand, dysphagia, regurgitation, ptyalism, halitosis, con- stipation, mucoid stools, hematochezia, and melena are usually best approached initially by other means (e.g., physical examination, radiology, ultrasonography, endos- copy, laparotomy, and/or biopsy).
