Modeling Study Shows Blood-Based CRC Screening Could Prevent More Deaths Than Stool Tests
Posted on 19 Oct 2026
Colorectal cancer (CRC) screening depends on patient participation and completion of follow-up colonoscopy after an abnormal noninvasive result. Access barriers can make both steps difficult, particularly in medically underserved communities. Highlighting the potential value of alternative screening options, new modeling data suggest that a blood-based test could improve screening adherence and avert more CRC deaths than stool-based testing.
Guardant Health’s (Palo Alto, CA, USA) Shield is a noninvasive blood-based CRC screening test that uses methylation partitioning cell-free DNA (mp-cfDNA) technology to detect colorectal cancer-associated alterations. It is intended for adults aged 45 or older at average risk for the disease and is not intended for high-risk individuals.
Shield can be considered alongside guideline-recommended noninvasive CRC screening options and can be completed during a healthcare visit. As with other noninvasive approaches, an abnormal result requires further evaluation. A positive Shield result raises concern for colorectal cancer or advanced adenoma and should prompt referral for colonoscopy.
New data presented at the American College of Gastroenterology 2026 Annual Meeting examined blood-based screening and adherence to follow-up colonoscopy. A modeling study of adults aged 45 to 75 projected lifetime health outcomes compared with other noninvasive tests, incorporating real-world evidence on follow-up colonoscopy adherence. The model suggested that blood-based testing could increase colonoscopy use by bringing more patients into the screening pathway.
When longitudinal screening adherence and real-world follow-up colonoscopy adherence were included, blood-based screening generated 679 colonoscopies per 1,000 simulated individuals over a lifetime, compared with 113 for fecal immunochemical testing (FIT) and 326 for multitarget stool DNA (mt-sDNA) testing. It also averted 12 CRC deaths per 1,000 simulated individuals, compared with six for FIT and nine for mt-sDNA testing.
Complementing these modeled findings, a separate study of Shield implementation at two rural health clinics in South Carolina reported 99% real-world adherence, compared with reported average adherence rates of 28% to 71% across CRC screening overall.
“Today’s research continues to reinforce the data we’ve seen across Guardant’s robust real-world evidence: blood-based screening meaningfully closes gaps in colorectal cancer screening participation with a significant lift in underserved communities that face some of the most persistent access barriers,” said Sam Asgarian, Guardant Health's VP of Clinical Affairs.
“For the first time, we’ve been able to correlate the impact of real-world follow-up colonoscopies and screening adherence with the modeling studies of the Shield blood test. We're proud to present this compelling research with our collaborators at ACG and to continue to demonstrate Shield’s role as a clinically meaningful alternative to traditional screening methods,” Asgarian added.
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