Your 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.
Jun. 18, 2011