What you can expectBy Mayo Clinic Staff
There are several types of fecal occult blood tests, each with a different approach to collecting and testing stool. They include:
Guaiac fecal occult blood test (gFOBT). Your doctor typically gives you a test card with room for two or three samples or two or three test cards.
You collect a stool sample from each of two or three bowel movements in a clean container, usually taken on consecutive days, and then use an applicator stick to apply a smear of stool to a specific area of a card.
After the samples are dry, you return them to your doctor or a designated lab, by mail or in person.
Flushable reagent pad or tissue. You can get this kit at a store without a prescription.
You place the pad or tissue in the toilet bowl after a bowel movement, usually on three consecutive days. The pads change color when blood is present.
You then report the changes to your doctor, usually on a mail-in form.
Immunochemical fecal occult blood test (iFOBT, or FIT). The collection method for this test may depend on the manufacturer, but typically, you use a special spoon or other device to collect a sample of stool and store it in a collection container that comes with the test kit.
The collection container is then returned to your doctor or a designated lab, by mail or in person.
Immunochemical testing is newer than gFOBT. It doesn't require any dietary restrictions before sample collection, and testing can often be performed on a random stool sample. Immunochemical testing is also more sensitive than is gFOBT.
For accurate results, follow the instructions and return the samples promptly.
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.