Guardant Health, Inc / "Shield Post-Approval Study" Study Sponsor and Protocol Number: Guardant Health, Inc / "Shield Post-Approval Study" / 07-GI-003 Specialty: Oncology/Cancer Screening Type: Post-Approval Study Inclusion: Age 45-81 Considered as being "average risk" for Colorectal Cancer (CRC) Patient agrees to comply with study procedures and associated standards of care assessments (colonoscopy) Exclusion:Undergoing a colonoscopy for the investigation of symptomsPersonal history of CRC, defined as having one or more first-degree relatives (parent, sibling or child) diagnosed with CRC at any ageKnown diagnosis of inflammatory bowel disease