ACS Adds Blood Test to Colorectal Cancer Screening Options
For the first time, the American Cancer Society has added a blood test to its recommended colorectal cancer screening options, a significant shift aimed at increasing screening rates among the more than 50 million eligible Americans who remain unscreened. The updated guidelines, released Wednesday, include Guardant Health’s Shield blood test as a new option, though the organization emphasizes it is not intended to replace colonoscopies, which remain the gold standard.
The New Recommendation
The Shield blood test, manufactured by California-based Guardant Health (Nasdaq: GH) and approved by the FDA in 2024, works by detecting DNA fragments released by cancerous tumors in the bloodstream. According to NBC News, the ACS recommends the test primarily for patients who decline or cannot undergo other screening methods such as colonoscopies or stool-based tests.
“About a third of Americans are not up to date with colorectal cancer screening,” said Dr. William Dahut, chief scientific officer of the American Cancer Society. Adding a blood test could “dramatically increase” the number of people screened for colorectal cancer, which is the nation’s top cause of cancer death in people under age 50.
Effectiveness and Limitations
The ECLIPSE trial, published in the New England Journal of Medicine, found the Shield test is 83% effective at detecting colorectal cancers. However, it is significantly less effective at detecting early-stage cancers and precancerous polyps, with approximately 13% sensitivity for advanced precancerous lesions. By comparison, colonoscopy has roughly 90% sensitivity for detecting advanced polyps.
Dr. Scott Kopetz, a gastrointestinal medical oncologist at MD Anderson Cancer Center, expressed both optimism and caution. “This is better than nothing, for sure,” he told NBC News. “The concern is that we’re going to lose ground in our battle for colorectal cancer prevention and early detection, that this is going to reduce the quality of screening that some of these patients may otherwise have received.”
Broader Screening Expansion
The updated guidelines also include new at-home stool-based tests, including a next-generation DNA stool test (Cologuard) and a new RNA stool test (ColoSense). The ACS continues to recommend that everyone at average risk for colorectal cancer start screening at age 45, consistent with its 2018 guideline update.
Andrew Wolf, MD, professor emeritus at the UVA School of Medicine and lead author of the guideline update, emphasized the practical philosophy behind the changes: “The most effective screening test is the one that the patient completes.”
Insurance and Regulatory Landscape
The ACS recommendation does not automatically trigger insurance coverage. Under the Affordable Care Act, private insurers must cover preventive services rated A or B by the U.S. Preventive Services Task Force (USPSTF), which has not yet included blood tests in its colorectal cancer screening guidelines. The Shield test currently costs $895 out of pocket.
As USA Today reported, the political landscape adds further uncertainty. Earlier this month, HHS Secretary Robert F. Kennedy Jr. fired top leaders of the USPSTF, leaving the future of the group’s recommendations uncertain. Dr. Arif Kamal, chief patient officer for the ACS, expressed hope that the task force may update its guidelines later this year.
Rising Cancer Rates Drive Urgency
Colorectal cancer is the second-leading cause of cancer death in the United States, with approximately 55,000 deaths expected in 2026. More than 108,000 new cases of colon cancer and nearly 50,000 cases of rectal cancer are projected to be diagnosed this year. Alarmingly, colorectal cancer is now the leading cause of cancer death in people under age 50, a trend that has driven the ACS to expand screening options.
Dr. Kimmie Ng, director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute, underscored the importance of the update: “Getting screened is more important than ever. Having a variety of different options available to people to encourage uptake of screening is really quite important.”
What’s Next
The Shield blood test should be repeated every three years, while stool-based tests are recommended every one to three years and colonoscopies every 10 years. Any positive result from a non-colonoscopy screening test must be followed up with a timely colonoscopy.
AmirAli Talasaz, co-CEO of Guardant Health, called the ACS inclusion “a momentous step forward” in reaching unscreened Americans. The updated guidelines are available in the ACS journal CA: A Cancer Journal for Clinicians.
Whether the expanded options will meaningfully increase screening rates — and whether insurance coverage will follow — remains to be seen. But for millions of Americans who have avoided colorectal cancer screening, there is now a new, simpler option available.