Like FIT, the stool DNA test  detects microscopic amounts of blood in stool, but also looks for certain DNA changes that are found in cancerous tumors or precancerous polyps. 

Cells from precancerous and cancerous lesions with certain mutations often shed DNA biomarkers into the stool, where this test can detect them.

Because DNA markers may be present in only very small quantities in stool, sensitive laboratory methods are used to detect the markers. The stool DNA test has high detection rates of early-stage colon cancer.

Please watch this video explaining the importance of Stool DNA/fecal immunochemical (FIT)-DNA test for your colorectal cancer screening

Credits: American Gastroenterological Association