Ultra-sensitivity Quantitative Fecal Immunochemical Test in Detecting Colorectal Advanced Adenoma and Colorectal Cancer

Inclusion Criteria: * 50-75 years old people; * People sign an "informed consent form" Exclusion Criteria: * People with history of colorectal surgery; * People with history of colorectal cancer; * People with history of other diseases that may produce fecal blood, such as inflammatory bowel disease, ischemic enteritis, vascular alformation of intestine, intestinal tuberculosis or Non-Hodgkin's lymphoma involving digestive tract; * People with symptoms including visible rectal bleeding, hematuria, hemorrhoid bleeds, severe and acute diarrhea and watery stool; * People are in pregnancy, lactation or menstrual phase; * People with severe congestive heart failure or other sever disease cause cannot tolerate colonoscopy.