NHS trials 'holy grail' blood test that detects 50 cancers with 62% accuracy

A blood test that hunts for more than fifty kinds of cancer is moving through NHS trials, and the early numbers suggest it could reshape how doctors catch the disease before it announces itself with symptoms. The Galleri test works by finding DNA fragments in the bloodstream—genetic material shed by cancer cells—and reading them like a fingerprint. When researchers ran the Pathfinder 2 study, they found that when the test flagged a cancer signal, it was right 62% of the time. More striking: it correctly said "no cancer here" in 99.6% of people who actually didn't have the disease, potentially sparing thousands from unnecessary follow-up scans and biopsies.

The test's real power lies in what it catches and when. Of the new cancers Galleri detected in the trial, more than half were caught at stage one or two—the earliest phases when treatment tends to work better and can be gentler on the body. The test also identified where the cancer originated in 92% of cases, which means doctors know immediately whether they're dealing with a lung tumor or a pancreatic one, cutting through the diagnostic fog that usually requires multiple imaging studies. When researchers modeled what would happen if Galleri ran alongside existing screening programs for breast and bowel cancer, the number of cancers found in a year jumped more than sevenfold. In the actual trial, the test detected a signal in 216 people, and 133 of them were subsequently diagnosed with cancer.

Sir Harpal Kumar, who leads international business at Grail, the company that developed Galleri, and formerly headed Cancer Research UK, called the findings impressive. He framed the potential this way: if the NHS trial comes back positive—results are expected mid-2025—the chance to find far more cancers before they cause symptoms could mean catching them at stages where curative treatment becomes possible rather than merely palliative. The modeling suggests the test would work best as an annual screening tool starting at age fifty, when cancer incidence climbs sharply. Younger people with a personal history of cancer or genetic risk factors might benefit too, though the economics shift below that age.

The stakes of early detection are substantial. Research published in BMJ Open found that an annual blood test for cancer could reduce late-stage diagnoses by nearly half and prevent 21% of deaths within five years compared to standard care. That's not a cure—Galleri is a detection tool, not a treatment—but it's the difference between finding a cancer when surgery or targeted therapy can work and finding it when the options narrow. The test costs money and carries the risk of false positives that send people down diagnostic pathways they didn't need. But the trial data suggests those false positives are rare enough that the math tilts toward screening.

What happens next depends on the NHS trial. The health service is testing how well Galleri works in real-world screening of people without symptoms—the people who would actually use it if it becomes available. If those results hold up, the question shifts from whether the test works to how quickly it can be rolled out and who gets access first. The test is already being used in some private settings and in research contexts. The NHS decision will determine whether it becomes a standard tool in the cancer-fighting arsenal or remains a specialized option for those who can afford it. For now, the blood test sits at the edge of routine practice, waiting for the next set of results to decide whether it moves in.