Usually done as a part of routine stool analysis
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).
Blood may show up in your stool because of one or more of the following conditions:
Gastrointestinal bleeding may be microscopic, so you can’t see it. (Doctors call that “occult” blood.) Or you may easily see it as red blood, or black tar-like
Because certain foods can alter some of the tests’ results, don’t eat these foods for 48 to 72 hours before you take the test:
You may need to stop taking certain medicines 48 hours before the test. Ask your doctor about that.