This study is to Evaluate the diagnostic sensitivity of the serum metabolite based PrecogColo Dx test for advanced colorectal neoplasia Screening, including advanced adenoma and colorectal cancer. There are two steps in this study. Firstly, the diagnostic model is established based on tumor-specific and gut-microbiome related serum metabolites. Secondly, the sensitivity, specificity and accuracy of the diagnostic model is evaluated in detecting advanced adenoma and colorectal cancer stages in an independent multi-centered cohort.

Subjects aged >45 at average risk for development of CRC will be enrolled. Subjects will complete the PrecogColo Dx test, followed by completion of a screening colonoscopy. . Results from PrecogColo Dx test were compared to the results of an optical colonoscopic examination, and histopathological diagnosis of all significant lesions discovered during the colonoscopy, in order to determine the sensitivity for CRC and advanced adenoma, respectively, as well as determining specificity of non-advanced neoplasia individuals. Histopathological results from biopsied tissue or excised lesions were categorized based on the most clinically significant lesion present by a central pathologist.

Inclusion Criteria:

1. Subject is ≥ 45 years of age at the time of enrollment.
2. Subject presents for a screening colonoscopy.
3. Subject has no symptoms or signs that require immediate, or near term, referral for diagnostic or therapeutic colonoscopy.
4. Subject is able and willing to sign informed consent.

Exclusion Criteria:

1. Patients received tumor treatment prior to the drawn of blood sample, including surgical resection, neoadjuvant chemotherapy, neoadjuvant chemoradiotherapy and targeted therapy.

2. Patients received antibiotics within 2 weeks.

3. Patients with indications of emergency surgery, including bleeding, obstruction and perforation.

4. Patients who are positive for Human Immunodeficiency Virus (HIV).

5. Patients with abnormal liver and kidney function.

6. Patients with the history of inflammatory bowel disease.

7. Patients who had history of other malignancies.

8. Subject has a diagnosis or medical history of any of the following conditions:

   1. Familial adenomatous polyposis (also referred to as "FAP", including attenuated FAP and Gardner's syndrome)
   2. Hereditary non-polyposis CRC syndrome (also referred to as "HNPCC" or "Lynch Syndrome")

Subjects 45 years of age and older who are eligible for colorectal cancer screening and scheduled for a screening colonoscopy. Approximately 2,000 subjects will be targeted for enrollment.