The primary objective is to determine sensitivity, specificity, positive predictive value and negative predictive value of a bi-target stool DNA testing (the methylation status of SDC2 and SFRP2) for colorectal cancer and advanced precancerous neoplasm(including advanced adenoma and advanced serrated lesions) screening, using colonoscopy as the reference method. Lesions will be confirmed as malignant or precancerous by histopathologic examination.

The secondary objective is to compare the performance of the bi-target stool DNA testing to a commercially available fecal immunochemical test (FIT) assay, both with respect to cancer and advanced precancerous neoplasm. Lesions will be confirmed as malignant or precancerous by colonoscopy and histopathologic examination.

This study is a multi-center diagnostic test led by the National Clinical Research Center for Digestive Disease (Shanghai) (Department of Gastroenterology, Changhai Hospital, Navy/Second Military Medical University), which is conducted at about 30 digestive endoscopy centers nationwide in China, with the expectation of including approximately 4,800 patients. Subjects willing to conduct colonoscopy examination will be asked to collect stool sample prior to bowl preparation for stool DNA test and commercially available FIT assay. The basic characteristics of subjects, bowel preparation method and quality, and related information of colonoscopy are recorded in detail. Colonoscopy and histopathologic examination are used as reference.

Inclusion Criteria:

1. Age between 40 to 85 years old, the gender is not limited
2. Willing to provide written consent
3. Able to provide stool sample

Exclusion Criteria:

1. Unwilling to provide stool samples
2. Subject with contraindications for bowel preparation or colonoscopy
3. Subject with known colorectal polyps but not removed
4. Subject with inflammatory bowel disease
5. History of colonoscopy within 1 year
6. History of colorectal cancer
7. History of hereditary colorectal cancer syndrome (including polyposis)
8. Active lower gastrointestinal bleeding
9. Pregnancy
10. Subject taking anticoagulants such as aspirin and warfarin, or who have coagulopathy
11. Subject clinically highly suspected with gastrointestinal cancer
12. Other conditions deemed not suited for the study by investigators

Elimination Criteria:

1. Ask to withdraw from the study
2. Unable to get a stool sample
3. Invalid stool samples to test
4. Poor or inadequate bowel preparation
5. Failed to complete the colonoscopy

Subjects who referred to the outpatient and received colonoscopy.