<P> Fecal occult blood (FOB) refers to blood in the feces that is not visibly apparent (unlike other types of blood in stool such as melena or hematochezia). A fecal occult blood test (FOBT) checks for hidden (occult) blood in the stool (feces). </P> <P> Other tests look for globin, DNA, or other blood factors including transferrin, while conventional stool guaiac tests look for heme . </P> <P> Fecal occult blood testing (FOBT), as its name implies, aims to detect subtle blood loss in the gastrointestinal tract, anywhere from the mouth to the colon . Positive tests ("positive stool") may result from either upper gastrointestinal bleeding or lower gastrointestinal bleeding and warrant further investigation for peptic ulcers or a malignancy (such as colorectal cancer or gastric cancer). The test does not directly detect colon cancer but is often used in clinical screening for that disease, but it can also be used to look for active occult blood loss in anemia or when there are gastrointestinal symptoms . </P> <P> The stool guaiac test for hidden (occult) blood in the stool can be done at home or in the doctor's office, or can be performed on samples submitted to a clinical laboratory . Testing kits are available at pharmacies in some countries without a prescription, or a health professional may order a testing kit for use at home . If a home fecal occult blood test detects blood in the stool it is recommended to see a health professional to arrange further testing . </P>

What is a positive stool exam for occult blood significant for