5 Things to Know About Multicancer Blood Tests

February is National Cancer Prevention Month¹ and April is Cancer Prevention and Early Detection Month.² Sandwiched in between is March, designated as Colorectal Cancer Awareness Month, Kidney Cancer Awareness Month, and Multiple Myeloma Awareness Month.^3,4 There is no better time than the present to talk about how a simple blood draw could change cancer screening. No such test is currently approved by the FDA—and keep in mind, these tests are not meant to replace screening—but there is palpable excitement around their promise, especially in light of the positive-trending results seen with the US Galleri trial (NCT05611632), despite the primary end point not being met.⁵

Here are 5 things to know about these tests, also known as liquid biopsies, and the science behind them.

1. A Single Blood Draw Could Screen for More Than 50 Cancers at Once

The blood sample is analyzed for tiny fragments of cancer DNA—biomarkers—via methylation patterns in cell-free DNA^6,7; these are the chemical markers that can signal whether abnormal cells are present and even suggest where in the body a tumor might be located.⁸ In a real-world study published in Nature Communications, researchers led by Ochsner Cancer Institute oncologist Marc R. Matrana, MD, found the Galleri test (Grail) predicted the cancer’s origin with 87% accuracy,⁹ and in a UK-led study among a prespecified group of 12 deadly cancers, results trended favorably toward fewer stage III to IV cancers.⁵ For cancers like pancreatic, ovarian, and esophageal—diseases with no routine screening tests and notoriously poor survival rates—that speed could theoretically be lifesaving.

2. The Technology Carries Lessons and Open Questions

In February 2026, Grail announced results from the NHS-Galleri trial (ISRCTN91431511), to date the largest randomized controlled study of a multicancer detection test ever conducted, enrolling 142,000 adults aged 50 to 77 years across England over 3 years.⁵ The headline finding was disappointing: The test failed to produce a statistically significant reduction in combined stage III to IV cancer diagnoses, the primary end point the trial was designed to achieve. Outside researchers were blunt. “The study failed,” said Adewole Adamson, MD, MPP, University of Texas at Austin. “End of story.” Richard Houlston, FMedSci, Institute of Cancer Research in Britain, said the results “don't support rollout within the American health care system.”¹⁰

Additional drawbacks associated with these tests include false-positive results; the economic burden, with tests frequently running several hundred dollars; lack of long-term data; and privacy considerations.¹¹

REFERENCES

3. Data Show Meaningful Progress in Detection

Although experts pointed to the missed primary end point, Grail highlighted a different signal buried in the numbers: a meaningful reduction in stage IV diagnoses specifically, alongside a 4-fold improvement in overall cancer detection rate compared with standard screening alone.^5,10 For the 12 deadliest cancer types tracked, stage IV diagnoses fell by more than 20% in the second and third rounds of annual screening. These cancers were anus, bladder, colorectal esophagus, head and neck, liver/bile duct, lung, lymphoma, myeloma/plasma cell neoplasm, ovary, pancreas, and stomach.

“When cancer is detected before distant metastatic spread, we can often treat with curative intent,” said Charles Swanton, MBPhD, an NHS-Galleri chief trial investigator from University College Hospital London, “combining surgery, radiotherapy, and systemic therapy in an effort to eradicate all disease.”¹⁰ Grail also noted that the test’s positive predictive value and diagnostic resolution appeared to improve as physicians gained experience—suggesting the technology’s impact could strengthen with wider adoption.⁵

4. Coverage Could Soon Be Within Reach for Millions

Despite waiting for FDA approval, Galleri has been sold in the US since 2021¹⁰ under the Clinical Laboratory Improvement Act regulatory pathway, which allows certain laboratory-developed tests to reach consumers without prior review and with doctors’ orders.¹² Very few insurers currently cover multicancer early detection tests, and patients primarily pay out of pocket for them, but that could soon change. In February, Congress passed legislation that will facilitate the establishment of a pathway to Medicare coverage for the tests, but only after FDA approval.¹³ President Donald J. Trump signed the Nancy Gardner Sewell Medicare Multi-Cancer Early Detection Screening Coverage Act into law on February 3.

5. Testing Is Just the Beginning

Cancer kills more than 600,000 Americans each year, according to the American Cancer Society, and a significant proportion of those deaths involve cancers for which there is no routine screening.¹⁴ The goal behind multicancer blood tests is straightforward: catch the cancer earlier, treat the cancer more successfully, and save more lives. But early detection is not automatically a cure, and diagnosing cancer sooner does not always translate to living longer. Additional testing is needed to confirm a diagnosis, such as scans and biopsies, and in addition to the threat of false-positive results previously mentioned, there is also potential for false-negative results.¹⁵