A blood test that can flag Alzheimer’s risk a decade before symptoms appear, a UK trial now recruiting patients through memory clinics to bring that test into the NHS and a three-year standoff over whether the health service can actually afford to treat the disease once it is found. The science of detecting dementia early is advancing faster than the system built to act on it.

Dementia has long been defined by delay. Diagnosis in England typically takes around a year from first seeing a GP, and for people with young-onset dementia it can take as long as four years, according to Alzheimer’s Society. An estimated third of people living with dementia in the UK remain undiagnosed altogether. That gap matters more than it used to, because for the first time there are treatments that can slow the disease in its earliest stages, and blood tests that can identify who is at risk before symptoms even begin. The problem, increasingly, is not whether the science works. It is whether the NHS is set up to use it.

A Blood Test That Looks a Decade Ahead

At the Alzheimer’s Association International Conference in London in July, researchers presented findings, simultaneously published in JAMA, showing that a blood test measuring a protein called p-tau217 can predict a person’s risk of future cognitive decline years before any symptoms appear. The study followed nearly 2,700 cognitively healthy adults, average age 70, from six major Alzheimer’s research groups, tracking them for an average of almost five years and some for more than a decade.

The results were striking. Cognitively healthy adults with very high p-tau217 levels, more than twice the study average, had an estimated 78% risk of developing cognitive impairment within ten years, and roughly a one-in-three chance within five. Even those with only moderately elevated levels carried a meaningful risk, around 15% at five years and 45% at ten. Crucially, the blood test added predictive information beyond what brain scans and genetic testing already provided. Rachel Buckley of Mass General Brigham, the study’s lead author, described the findings as some of the clearest evidence yet that elevated p-tau217 “may help detect dementia risk years earlier, even in adults with no noticeable memory or thinking problems.” Reisa Sperling, the study’s senior author, noted that the information becomes more powerful still if ongoing trials confirm that treatment started before symptoms appear can actually prevent decline.

Bringing the Test to the NHS

The science exists; the infrastructure to use it in Britain is now the focus of a dedicated effort. The Blood Biomarker Challenge, a multi-million-pound programme funded by Alzheimer’s Research UK, Alzheimer’s Society, the National Institute for Health and Care Research and Gates Ventures, including £5 million raised by players of the People’s Postcode Lottery, is running two parallel studies designed to build the evidence needed to bring blood tests into routine NHS diagnosis. The READ-OUT study, led by Professor Vanessa Raymont with Dementias Platform UK researchers at Oxford and Cambridge, is testing multiple existing and novel blood tests across a range of dementia types. The ADAPT study, led by Professor Jonathan Schott and Dr Ashvini Keshavan at UCL, is focused specifically on p-tau217 and began recruiting its first participants through memory clinics across the UK in September 2025, after the team had validated the test’s accuracy and performance.

The stakes of getting this right are practical rather than abstract. Current diagnostic routes, brain scans and lumbar punctures, are slow, uncomfortable and unevenly available across the country. Fiona Carragher, Director of Research and Influencing at Alzheimer’s Society, has argued that “new drugs targeting early-stage Alzheimer’s disease are just around the corner. But without a diagnosis, people simply won’t be able to access them if they are approved.” Dr Susan Kohlhaas of Alzheimer’s Research UK has separately warned that as awareness grows, more people are likely to come forward for testing, and that “the NHS doesn’t possess the required levels of diagnostic infrastructure to cope with this growing demand.”

The Drugs That Diagnosis Is Racing Towards

That last point exposes an uncomfortable tension, because the treatments a faster diagnosis would unlock are themselves not yet available on the NHS. Donanemab (Kisunla, made by Eli Lilly) and lecanemab (Leqembi, made by Eisai), the two amyloid-clearing antibody drugs that represent the first disease-modifying treatments for early Alzheimer’s, have been rejected for routine NHS use by the National Institute for Health and Care Excellence three times, most recently in June 2025. NICE’s appraisal committee concluded that although the drugs delay progression from mild to moderate Alzheimer’s by around four to six months, the benefit was too small relative to their cost, including the substantial expense of infusion and monitoring, to represent good value for NHS resources.

Following appeals from both manufacturers, NICE agreed to reconsider two specific elements of its assessment, how it values the benefit to unpaid carers and how it costs drug administration, with a further committee meeting held on 8 July 2026. As of 29 July 2026, according to The Pharmaceutical Journal, Eisai had accepted the committee’s underlying assumptions and entered commercial discussions with NHS England to explore whether a price could be agreed that would allow lecanemab onto the NHS. Lilly had not yet done the same for donanemab, and no deadline for a decision has been set. Hilary Evans-Newton, Chief Executive of Alzheimer’s Research UK, called the repeated rejections a warning sign for a government that “pledged to make the UK a global leader in dementia treatments,” arguing that with more than 30 Alzheimer’s drugs now in late-stage trials globally, the pressure on the system to prepare will only grow.

Two Systems Moving at Different Speeds

Taken together, the picture in dementia right now is one of a widening gap between what can be detected and what can be treated. The blood test science is moving quickly and is already being tested in NHS memory clinics. The drugs it would eventually help direct people towards remain stuck in a cost-effectiveness negotiation that has now run for more than three years and shows no sign of resolving cleanly in either direction. Both processes matter, and neither is complete without the other: a faster diagnosis is of limited value if there is nothing new to offer once someone receives it, and a treatment sitting unused because too few people are diagnosed early enough to benefit from it is its own kind of failure.

What is different about 2026 is that both problems are now being worked on in parallel, with real deadlines and real commercial negotiations attached, rather than sitting as separate, disconnected ambitions. Whether that translates into shorter waits and wider access will depend on decisions still being made in NICE committee rooms and NHS England negotiations as this goes to press.

Sources include the Alzheimer’s Association International Conference, JAMA, Alzheimer’s Society, Alzheimer’s Research UK, the National Institute for Health and Care Excellence and The Pharmaceutical Journal.