Free
E-newsletter
Subscribe to Housecall
Our weekly general interest
e-newsletter keeps you up to date
on a wide variety of health topics.
close window
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Results
By Mayo Clinic staffYour doctor will review the results of your stool DNA test and then share the results with you.
- Negative result. A test is considered negative if DNA markers common to colon cancer or precancerous polyps are not found in your stool.
- Positive result. A test is considered positive if DNA markers common to colon cancer or precancerous polyps are found in your stool sample. Additional evaluation — usually colonoscopy — would be recommended to determine whether you have cancerous or precancerous changes in your colon or other parts of your digestive system.
- False-negative result. A false-negative result — a negative test result when cancer is present — may occur if colon cancer or polyps do not harbor DNA markers targeted by the stool DNA test, or if markers are present in extremely low amounts. While next-generation stool DNA test methods appear to be capable of detecting most colon cancers and precancerous polyps, further study is needed to determine what the rate of false-negative results will be.
- False-positive result. A false-positive result — a positive test for cancer when no cancer is present — may occur in about 5 to 10 percent of people screened. False-positives could be due to the presence of tumors above the colon or to a problem with the test. When the stool DNA test result is positive but a follow-up colonoscopy is normal, your doctor may recommend further observation with another stool DNA test, evaluation of your upper gastrointestinal tract, a repeat colonoscopy or a combination of these. Research is being done to clarify the best way to manage false-positive results.
References
- 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.
- 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. CA: A Cancer Journal for Clinicians. 2008;158:130.
- Ahlquist DA. Next generation stool DNA testing: Expanding the scope. Gastroenterology. 2009;136:2068.
- Ahlquist DA. Molecular detection of colorectal neoplasia. Gastroenterology. 2010;138:2127.
- Lieberman D. Progress and challenges in colorectal cancer screening and surveillance. Gastroenterology. 2010;138:2115.
- Lansdorp-Vogelaar I, et al. Stool DNA testing to screen for colorectal cancer in the Medicare population: A cost-effectiveness analysis. Annals of Internal Medicine. 2010;153:368.
Find Mayo Clinic on