The American Cancer Society has updated its colorectal cancer screening guidelines to include a blood-based test option for adults 45 and older at average risk who decline visual or stool tests, marking the first formal recommendation of a blood test for screening.

Guardant Health's Shield blood test is FDA-approved and detects tumor DNA fragments, showing strong performance for detecting advanced cancers but limited sensitivity for early cancers and precancerous lesions; long-term survival benefits remain unproven.

A positive Shield result requires a prompt follow-up colonoscopy, ideally within six months, to complete the screening process.

Industry and patient advocates stress offering a range of screening options to boost uptake, aiming to raise overall screening rates and save lives.

Guidance emphasizes patient-centered decision-making, highlighting that understanding each test’s strengths and weaknesses helps patients choose the most acceptable option, potentially improving participation.

The guidelines and supporting study were published online by UVA Health’s panel led by Andrew Wolf, with disclosures noted in the accompanying paper.

Guardant argues the new option can reach patients who might otherwise remain unscreened.

The press release includes standard forward-looking statements and legal disclosures, noting risks and the need to update as market conditions and guidelines evolve.

Guardant Health notes that guideline inclusion reflects advances in screening technology and real-world data supporting increased participation and earlier detection.

The update targets more than 50 million Americans who remain unscreened and underscores multiple screening options to improve participation.

Screening recommendations cover adults 45 to 75 at average risk, with personal and family history guiding decisions; age thresholds and follow-up may vary for higher-risk populations.

Real-world adherence to Shield exceeds 90% in about 200,000 tested patients, with NEJM-supported evidence of high sensitivity, including 100% sensitivity for stage II and above cancers in the ECLIPSE study.