A diagnostic approach to occult blood in the stool.

Occult blood in the stool may be the first sign of otherwise asymptomatic colorectal cancer or other gastrointestinal disease. All patients over 40 should therefore have a rectal examination that includes a Hemoccult slide test. A rational diagnostic plan is essential to identify the source of occult blood in the stool. Most gastrointestinal cancer is operable if diagnosed early, so early detection of these lesions is imperative.