Various foods, dietary supplements and medications can affect the results of some fecal occult blood tests — either indicating that blood is present when it isn't (false-positive) or missing the presence of blood that's actually there (false-negative). To ensure accurate test results, follow your doctor's instructions carefully.
For about three days before the test, your doctor may ask you to avoid:
Jun. 18, 2011
- Certain fruits and vegetables, including broccoli and turnips
- Red meat
- Vitamin C supplements
- Pain relievers, such as aspirin, ibuprofen (Advil, Motrin, others)
- Fecal occult blood test: The test sample. American Association for Clinical Chemistry. http://www.labtestsonline.org/understanding/analytes/fecal_occult_blood/test.html. Accessed April 12, 2011.
- Fletcher RH. Tests for screening for colorectal cancer: Stool tests, radiologic imaging and endoscopy. http://www.uptodate.com/home/index.html. Accessed April 12, 2011.
- Labianca R, et al. Screening and diagnosis for colorectal cancer: present and future. Tumori. 2010;96:889.
- American Cancer Society guidelines for the early detection of cancer. American Cancer Society. http://www.cancer.org/docroot/PED/content/PED_2_3X_ACS_Cancer_Detection_Guidelines_36.asp?sitearea=PED. Accessed April 12, 2011.
- Lieberman D. Progress and Challenges in Colorectal Cancer Screening and Surveillance. Gastroenterology. 2010;138:2115.
- 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.
- Doppler JM (expert opinion). Mayo Clinic, Rochester, Minn. June 8, 2011.