The American Cancer Society on Wednesday expanded the colorectal cancer screening lineup for average-risk adults 45 and older, officially adding a blood test to the mix. Colonoscopy is still the gold standard, but the move gives clinicians another noninvasive option for people who refuse or never finish other tests. Public health leaders say the goal is simple: reach the millions of eligible Americans who still are not getting screened at all.
The guideline update, published in CA: A Cancer Journal for Clinicians and posted on the ACS website, names Guardant Health’s Shield as the FDA-approved blood-based screening option for adults 45 and up, according to the American Cancer Society. The ACS reiterates that average-risk adults should start screening at 45 and keep going through age 75 if they are expected to live more than 10 years. The society is clear that any positive result from a non-colonoscopy test still needs a prompt follow-up colonoscopy to actually complete screening.
How the tests compare
Large studies highlight some key trade-offs between convenience and prevention. In the ECLIPSE trial, published in the New England Journal of Medicine, Shield picked up about 83% of colorectal cancers but found only around 13% of advanced precancerous lesions. A formal CMS evidence review puts multitarget stool DNA and RNA tests higher when it comes to catching advanced adenomas. That shortfall in precancer detection is a major reason stool-based options remain the preferred noninvasive choice for cancer prevention, even if a simple blood draw may feel easier for many patients.
Who the blood test is for
The ACS recommends that blood-based screening be used mainly for people who decline or do not complete preferred screening tests, rather than as a go-to first option for everyone. The updated guidance also adds newer at-home stool kits to the recommended list - including Exact Sciences’ Cologuard and Geneoscopy’s ColoSense - which regulators and company summaries evaluated for their ability to detect both cancer and advanced precancerous growths. Stool tests are generally advised every three years and still offer stronger prevention benefits because they pick up more precancerous lesions.
Access and coverage
Shield received FDA approval in mid-2024, and the agency’s device page outlines its intended use as a screening tool for average-risk adults. Payer policy and Medicare coverage pathways for some molecular screening tests have been evolving since then. Guardant has highlighted low screening uptake - estimating that more than one in three eligible Americans are not current with screening - as a key reason to bring a blood test into the picture, and the company has been building lab and health system partnerships to increase access. Even as availability grows, clinicians stress that a positive stool or blood result only leads to full screening when it is followed by a timely diagnostic colonoscopy.
What readers should do
Bottom line: the best screening test is the one a person will actually get done, but the prevention edge still goes to colonoscopy and stool-based tests because they help find and remove precancerous polyps. Talk with your primary care clinician about which option works for your health history, insurance situation, and comfort level, and check out the American Cancer Society’s patient materials and guideline summary for plain-language comparisons and timing at the American Cancer Society. With more tools now on the table, the main aim of the update is to shrink the screening gap and catch more cancers early, when outcomes tend to be far better.
