Cologuard is the only stool-DNA screening test for detecting colon cancer that is approved by the Food and Drug Administration (FDA). Cologuard looks for changes in your DNA that could indicate the presence of colon cancer. It also checks for precancerous polyps that might be present in your colon. Cologuard finds 92% of colon cancers, even in early stages. In fact, it finds 94% of stage I and stage II cancers.