The fecal occult blood test (FOBT) is a lab test used to check stool samples for hidden (occult) blood. Occult blood in the stool may indicate colon cancer or polyps in the colon or rectum — though not all cancers or polyps bleed.
Doctor may recommend a fecal occult blood test to screen for colon cancer and evaluate possible causes of unexplained anemia.
A fecal occult blood test is considered negative if no blood is detected in your stool samples. A fecal occult blood test is considered positive if blood is detected in your stool samples. You may need additional testing such as a colonoscopy to locate the source of the bleeding.