Is blood the new stool? Status of blood tests for CRC screening

Colorectal cancer (CRC) screening has proven to decrease CRC incidence and mortality, with many countries providing faecal immunochemical tests (FIT) in screening programs. Effectiveness, however, is limited in the setting of low participation rates, which has prompted growing research into blood-based screening. While blood testing is anticipated to improve participation due to greater population acceptability, its readiness for widespread implementation remains unclear, and comparative accuracy data against FIT is needed. This article provides a systematic review and meta-analysis on blood-based CRC screening tests that have been directly compared to FIT, and summarises the evidence for broader program considerations, including analytical quality, consumer preferences, participation rates and cost effectiveness. The findings show that blood tests currently lack the sensitivity and cost-effectiveness to replace FIT in screening programs, and that their use should be limited to individuals unable or unwilling to complete FIT.