A fecal occult blood test (FOBT) is a noninvasive test (nothing enters the body). This test detects hidden (occult) blood in the stool. Such blood may come from anywhere along the digestive tract. Hidden blood in stool is often the first, and in many cases the only, warning sign that a person has colorectal disease, including colon cancer.

There are two types of FOBTs: 1) the traditional guaiac smear test (Hemoccult, Seracult, Coloscreen), and 2) the newer, flushable reagent pads (EZ DetectT, ColoCARE). They are both useful in detecting hidden blood in the stool, and are mainly used for colorectal cancer screening.

The tests differ in the way they are performed. The flushable reagent pads are available without a prescription at many drugstores. In contrast, the traditional guaiac smear test is completed and interpreted by a medical professional, and these tests are usually available from a laboratory or a doctor's office.

Many consumers prefer the flushable reagent pads because there is no stool handling and no laboratory processing. However, health care providers usually favor the guaiac tests because the large studies that have shown the benefits of colon cancer screening were done with guaiac tests.

See description under specific type of FOBT for how these tests are performed.

See description under specific type of FOBT.

See description under specific type of FOBT.