DefinitionBy Mayo Clinic Staff
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.
Typically, occult blood is passed in such small amounts that it can be detected only through the chemicals used in a fecal occult blood test.
If blood is detected through a fecal occult blood test, additional tests may be needed to determine the source of the bleeding. The fecal occult blood test can only detect the presence or absence of blood — it doesn't indicate potential sources of bleeding.
June 06, 2014
- Fecal occult blood test and fecal immunochemical test: The test. American Association for Clinical Chemistry. http://labtestsonline.org/understanding/analytes/fecal-occult-blood/tab/test. Accessed March 6, 2014.
- Fletcher RH. Tests for screening for colorectal cancer: Stool tests, radiologic imaging and endoscopy. http://www.uptodate.com/home. Accessed March 6, 2014.
- Fletcher RH. Screening for colorectal cancer: Strategies in patients at average risk. http://www.uptodate.com/home. Accessed March 7, 2014.
- Fecal occult blood test and fecal immunochemical test: The test sample. http://labtestsonline.org/understanding/analytes/fecal-occult-blood/tab/sample/. Accessed March 6, 2014
- Ask Mayo Expert. Colorectal cancer screening and surveillance. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2014.
- Levin B, et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: A joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology. 2008;134:1570.
- Flitcroft KL, et al. Colorectal cancer screening: Why immunochemical fecal occult blood tests may be the best option. BMC Gastroenterology. 2012;12:183.
- Medical devices: Fecal occult blood. U.S. Food and Drug Administration. http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/InVitroDiagnostics/HomeUseTests/ucm125834.htm. Accessed Feb. 28, 2014.
- Ghosh AK, editor. Mayo Clinic Internal Medicine Review. 8th ed. Rochester, Minn.: Mayo Clinic Scientific Press, New York: Informa Healthcare USA; 2008.
- Brink D, et al. Institute for Clinical Systems Improvement. Colorectal cancer screening. https://www.icsi.org/guidelines__more/catalog_guidelines_and_more/catalog_guidelines/catalog_prevention__screening_guidelines/colorectal/. Accessed Feb. 28, 2014.
- US Preventive Services Task Force. Screening for colorectal cancer: U.S. Preventive Services Task Force Recommendation Statement. Annals of Internal Medicine. 2008;149:627.
- Fecal occult blood tests. American Society of Clinical Oncology. http://www.cancer.net/navigating-cancer-care/diagnosing-cancer/tests-and-procedures/fecal-occult-blood-tests. Accessed March 21, 2014.