FIT-Fecal DNA Test

The U.S. Multi-Society Task Force of Colorectal Cancer has ranked the FIT-Fecal DNA Test as a tier 2 test. It is designed to detect microscopic blood as well as abnormal DNA in stool samples. It is a convenient  at-home test but it can be expensive. Both false positives and false negatives do occur. This test fails to detect 8% of cancers and 60% of large polyps that are at higher risk for becoming colon cancer. This test is not recommended if you have symptoms, personal history or belong to the high risk group.

What it is:

* The currently available FIT-Fecal DNA test is Cologuard® . This is a stool-based screening test for colorectal cancer that is used for people at average risk for colon cancer who are age 50 years or older. The cost is typically around $600.

* If positive, this test should be followed up with colonoscopy.

* If negative, this test should be repeated in three years.

What it’s NOT:

* A test for patients who have previously had colorectal polyps or cancer

* A test for patients with a strong family history of colon cancer


Other facts about Cologuard:

* It costs 20-30 times more than the other stool screening test (FIT) with only a modest improvement in performance.

* If positive, a diagnostic colonoscopy should be performed to determine if polyps or cancer are present in the colon. 

* It should be performed every three years, whereas screening colonoscopies can be performed every 10 years in people without any polyps or cancer history.

* It has a high false positive rate – especially in older patients.