Barriers to Diagnostic Colonoscopy After a Positive Stool-Based Screening Test: A Scoping Review.

Non-invasive stool-based colorectal cancer (CRC) screening (e.g., fecal immunochemical test [FIT], guaiac fecal occult blood test [gFOBT], multitarget stool DNA [mt-sDNA]) reduces CRC mortality only when a positive result is followed by timely diagnostic colonoscopy. We synthesized barriers and facilitators to completing diagnostic colonoscopy after a positive stool-based screening test. Guided by Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR), we searched PubMed and MEDLINE (Ovid) for English-language, peer-reviewed studies (October 2008- June 2025) reporting barriers, facilitators, or determinants of colonoscopy completion after a positive non-invasive stool-based CRC screening test (FIT, gFOBT, or mt-sDNA). Two reviewers independently abstracted study characteristics and coded barriers/facilitators, which were categorized using a socioecological framework (intrapersonal, interpersonal, organizational, community/environmental, policy). 38 studies directly examined colonoscopy follow-up after a positive non-invasive test. Recurrent barriers included fear/anxiety and low perceived risk (intrapersonal), weak provider recommendation and support (interpersonal), referral and tracking failures and scheduling delays (organizational), transportation and distance (community/environmental), and cost-sharing/coverage gaps (policy). Evidence specifically assessing rural-urban differences was limited. Barriers to diagnostic colonoscopy after a positive stool-based CRC screening test are multi-level and potentially modifiable through improved communication, navigation, and closed-loop tracking. Multicomponent approaches that combine clear communication, navigation and reminder systems, transportation supports, and reduced financial barriers may improve diagnostic completion and equity.