A groundbreaking clinical trial is underway in the United Kingdom, aiming to transform the way Alzheimer’s disease is diagnosed within the National Health Service (NHS). The study, which began recruiting participants in Essex in August 2025 and is now expanding to 19 additional NHS memory clinics across the country, centers on a simple blood test that could make diagnosis faster, more accurate, and more accessible for thousands of people living with dementia.
According to BBC, more than 1,000 people with suspected dementia will participate in the trial, known as the Alzheimer’s Disease Diagnosis and Plasma p-tau217 (ADAPT) study. The effort is led by researchers at University College London (UCL), with support from Alzheimer’s Research UK, the Alzheimer’s Society, and funding from the People’s Postcode Lottery. The hope is that this new diagnostic tool could revolutionize how clinicians identify Alzheimer’s, the most common form of dementia, and ultimately improve the lives of those affected by the disease.
Dementia is now the leading cause of death in the UK, yet experts estimate that nearly a third of people with the condition remain undiagnosed—a gap that leaves many without access to support, treatment, or the chance to plan for the future. As reported by Alzheimer’s Research UK, “Today, one in three people are living with dementia without a formal diagnosis. This is preventing them from being able to plan, having the support and treatments they need and taking part in research.”
Currently, the diagnostic process for Alzheimer’s is lengthy and often inconclusive. It typically relies on pen and paper memory tests, brain scans, and, in some cases, lumbar punctures. These “gold-standard” tests—such as amyloid PET scans and lumbar punctures—are invasive, costly (about £1,500 each), and rarely used, with only 2% of patients ever receiving them. In contrast, the new blood test costs around £100 and is far less invasive, offering a practical alternative for routine use.
The blood test works by detecting p-tau217, a biomarker that reflects the presence of both amyloid and tau proteins in the brain. These two proteins are hallmarks of Alzheimer’s disease, accumulating for up to 20 years before symptoms appear. As Professor Jonathan Schott, professor of neurology at UCL and chief medical officer at Alzheimer’s Research UK, explained, “We now have a blood test for Alzheimer’s disease that is backed by strong scientific evidence and provides comparable information to other gold-standard diagnostic tests such as PET scans and lumbar punctures yet is far more accessible, and cheaper.”
While the test itself is not a standalone diagnostic tool, research suggests that blood-based measurements of p-tau217 can detect the key proteins associated with Alzheimer’s as accurately as current methods. The trial aims to determine if integrating this test into routine NHS memory services can speed up diagnosis, guide further investigations, and improve how patients and clinicians interpret and respond to results.
All 1,100 participants in the ADAPT trial have mild to moderate cognitive impairment and will undergo a standard initial assessment. Half will receive their blood test results within three months, while the other half will be told after 12 months. The study will evaluate whether earlier access to results leads to faster diagnoses and influences clinical decision-making, as well as how it affects patients’ quality of life.
Professor Fiona Carragher, chief policy and research officer at the Alzheimer’s Society, highlighted the urgency of the challenge: “Dementia is the healthcare challenge of our generation and it will take a society to beat it.” She described the ADAPT trial as “pivotal,” noting that too often dementia is diagnosed late, which limits access to support, treatment, and opportunities to plan ahead. “Blood tests could offer a faster and more accessible route to diagnosis,” she said, adding, “The Blood Biomarker Challenge is committed to building the evidence needed to bring these innovative tests into NHS care, delivering real benefits for people living with dementia and their families.”
For many families, the promise of a quicker and more accurate diagnosis is deeply personal. Michael White, 75, who cares for his wife Kathryn, shared with The Independent, “A blood test like this would have helped to make a diagnosis right at the start and would have made a real difference to us. Hopefully initiatives like the Blood Biomarker Challenge will pave the way to change for other people in the future.” Kathryn White, 74, reflected on her own experience: “It took so long to receive a diagnosis of dementia. We knew there was something wrong and I was doing things like getting lost in places I was familiar with. It was a relief, in many ways, to have a diagnosis because it helped to make sense of it. The hardest thing for me has been having to stop driving.”
Steven Pidwell, 71, from north London, also emphasized the potential impact of a rapid, accurate blood test for Alzheimer’s. Speaking to BBC, he said, “I think it would mean everybody’s idea of Alzheimer’s would change. We would treat Alzheimer’s more like having a disability, rather than sort of a curse, and something we can’t talk about.”
The ADAPT trial is part of the larger Blood Biomarker Challenge, a multi-million-pound program supported by Alzheimer’s Research UK, the Alzheimer’s Society, and the People’s Postcode Lottery. The goal is to introduce blood tests for Alzheimer’s into the NHS by 2029, a timeline that reflects both the promise and complexity of integrating new diagnostics into a healthcare system under significant pressure.
Dr. Sheona Scales, director of research at Alzheimer’s Research UK, underscored the importance of sustained investment: “It also shows how decades of sustained investment in research is finally going to lead to breakthroughs people with dementia so desperately need.” Since 1999, Alzheimer’s Research UK has committed £37.8 million to projects aimed at improving dementia diagnosis, including blood tests, eye scans, and mobile brain scanners.
While the results of the ADAPT trial are expected within three years, researchers caution that the blood test is not yet able to predict who will develop Alzheimer’s in the future. Its current value lies in confirming a diagnosis in people already showing symptoms of memory or thinking problems. Nevertheless, the trial’s findings could be especially significant as new treatments for early-stage Alzheimer’s approach regulatory approval, making timely and accurate diagnosis more crucial than ever.
With the number of people affected by dementia in the UK expected to triple by 2050, the stakes could not be higher. As the ADAPT trial continues, its outcomes may well determine how—and how soon—the NHS can offer hope to the millions touched by Alzheimer’s disease. For now, those concerned about symptoms are encouraged to speak to their GP and consider registering for research participation, as every step forward brings the promise of a better future for patients and families alike.
