What is the likelihood they will find something on a colonoscopy if you had a positive fecal immunochemical test (for blood in stool)?

Heme + stool on FIT: At your age, finding something serious would be unusual. It could be hemorrhoids or contamination if it was done during a menstrual period. If you've had bowel habit changes such as more frequent stools or abdominal pains, it may be a good idea to pursue the colonoscopy. Another reason to pursue a colonoscopy would be if members of your family have had cancer in the digestive tract.