A blood-based colorectal cancer screening test has secured Medicare coverage and a recommendation from the American Cancer Society,
The test, Guardant Health’s Shield, was approved by the Food and Drug Administration in July 2024 as the first blood-based colorectal cancer screening test approved as a primary screening option for average-risk adults age 45 and older, according to the FDA.
Clinical data reviewed during the FDA process showed Shield detected 83% of colorectal cancers and 13% of advanced adenomas, or precancerous growths, reported Reuters. FDA advisers raised concerns about the advanced adenoma figure because those lesions can often be removed before they develop into cancer.
The American Cancer Society updated its colorectal cancer screening guidelines in May to include blood-based tests, naming Shield as the only blood-based test currently meeting the guideline criteria. ACS said the test is recommended only for individuals who decline or do not complete preferred screening tests.
In the same guideline update, ACS said blood-based tests demonstrated lower sensitivity than established stool-based tests for both advanced precancerous lesions and stage I cancers. The organization said studies predict blood-based tests will be less effective than stool-based tests and colonoscopy at reducing colorectal cancer incidence and mortality.
Guardant announced in March 2025 that the Centers for Medicare & Medicaid Services granted Shield Advanced Diagnostic Laboratory Test status. The company said Shield would be reimbursed at $1,495 for Medicare patients during an initial nine-month ADLT period beginning April 1, 2025.
By contrast, stool-based colorectal cancer screening tests are already established in national screening recommendations. The U.S. Preventive Services Task Force includes stool DNA-FIT testing among recommended colorectal cancer screening options for average-risk adults ages 45 to 75 and recommends the test every one to three years.
Exact Sciences said its Cologuard stool DNA-FIT test has been used approximately 20 million times since its launch in 2014 and is included in screening recommendations from both ACS and USPSTF.
Reuters reported that roughly one-third of eligible Americans remain unscreened for colorectal cancer, creating an opportunity for less invasive screening methods to reach patients who otherwise might forgo screening.
A recent article by the Washington Signal reported that Exact Sciences urged CMS to prioritize detection of advanced precancerous lesions, calling advanced adenoma detection “the single most important metric for cancer prevention.”
The article also said that former Health and Human Services Secretary Alex Azar, who joined Guardant Health’s board of directors in 2025, said proposed CMS requirements tying coverage of blood-based screening tests to advanced adenoma detection rates would “reduce access to screening” and “worsen disparities in cancer outcomes.”
Colorectal cancer remains the second-leading cause of cancer death in the United States. ACS estimates more than 154,000 Americans will be diagnosed with colorectal cancer this year and more than 52,000 will die from the disease.
