 to find 92% of colon cancers. 92%? Yep, even those in early stages. This was seen in a clinical study with patients 50 and older. Any positive results should be followed by a diagnostic colonoscopy. False positive and negative results may occur. Cologuard is not a replacement for colonoscopy in high-risk patients. Do not use if you have had adenomas, have inflammatory bowel disease and certain hereditary syndromes, or a personal or family history of colon cancer.