A major UCL-led clinical trial, aiming to transform the diagnosis of Alzheimer's disease through a simple blood test, is now welcoming its first participants who will be recruited via memory clinics across the UK.
The ADAPT (Alzheimer's Disease Diagnosis and Plasma pTau217) team, led by Professor Jonathan Schott and Dr Ashvini Keshavan (both UCL Queen Square Institute of Neurology) is investigating whether a blood test that measures the protein p-tau217 can improve the early and accurate diagnosis of Alzheimer's disease. Demonstrating its value in clinical practice could help deliver earlier and fairer access to diagnosis and future treatments across the NHS.
The trial will examine whether providing the blood test results to patients and their clinicians near the start of an assessment for memory and thinking concerns is able to aid diagnosis and guide decisions on further investigations and treatments. The study aims to recruit 1,100 participants through NHS memory services and will include people from diverse geographic, ethnic and economic backgrounds, and those living with other health conditions to ensure the findings are relevant and inclusive of the broader population.
This landmark trial forms part of the Blood Biomarker Challenge, a multi-million-pound programme supported by Alzheimer's Society, Alzheimer's Research UK and players of People's Postcode Lottery. The initiative aims to determine if the blood test is reliable in a broad range of patients that would make it a form of diagnostics that matches the accuracy of current methods.
Alzheimer's disease, the most common cause of dementia, is linked to the build-up of two key proteins in the brain called amyloid and tau. One of the most promising biomarkers in the blood, p-tau217, reflects the presence of both amyloid and tau in the brain. Emerging evidence suggests that blood tests such as plasma p-tau217 can detect these proteins as accurately as current methods such as amyloid PET scans and lumbar punctures, and therefore may have the potential to offer a less invasive, more accessible, and cost-effective alternative.
Although these blood tests are not standalone diagnostic tools, they could be used as part of a wider clinical assessment to confirm the diagnosis of Alzheimer's disease for people who already have memory or thinking problems.
The ADAPT team have already assessed and validated the accuracy and performance of the p-tau217 blood test which is now established in the National Hospital for Neurology and Neurosurgery's NHS clinical laboratory. The team is now running a clinical trial to demonstrate that the test is accurate, cost-effective, and suitable for integration into routine care across NHS memory services.
The first ADAPT trial location began recruitment in Essex Partnership University NHS Foundation Trust in late August with 19 additional specialist NHS Centres planned across the UK. All participants in the ADAPT study will receive standard diagnostic assessments and care. Half of the planned participants will receive their blood test results within three months of being assessed for the first time in their memory service, while the other half will receive theirs after 12 months.
The team will assess whether providing results earlier helps speed up diagnosis, guides decisions about further investigations, and influences how both patients and clinicians interpret and respond to the results. Researchers will also assess the impact of blood test results on quality of life using a system called the EQ-5D-5L, a standardised instrument for measuring health-related quality of life, as well as healthcare costs, and their relevance to people from diverse ethnic backgrounds or with conditions like kidney disease.
Professor Jonathan Schott of the UCL Queen Square Institute of Neurology and Chief Medical Officer at Alzheimer's Research UK, said: "We are thrilled to welcome participants onto the ADAPT trial - a critical part of the Blood Biomarker Challenge, which we hope will take us a step forward in revolutionising the way we diagnose dementia.
"After decades of research, 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.
"Currently only about 2% of people diagnosed with Alzheimer's have access to one of these gold-standard diagnostic tests. While identifying Alzheimer's disease early and accurately is already important for enabling access to current therapies and planning care, it will become even more critical as a new generation of treatments emerge that can slow down the decline of memory and thinking. Timely diagnosis will be key to ensuring these advances reach the people who need them most."
Dr Ashvini Keshavan (UCL Queen Square Institute of Neurology) added: "An important characteristic about this trial is that it is indexing the impact of the blood test on onward care and management. Our trial is not about confirming accuracy of the blood test, as we have already done this in prior research; rather, this is about showing that it actually makes a difference to patients and hopefully can help them to get a diagnosis sooner."
Professor Fiona Carragher, Chief Policy and Research Officer at Alzheimer's Society, said: "Our recent Lived Experience Survey revealed that only a third of people with dementia felt their experience of the diagnosis process was positive, while many reported being afraid of receiving a diagnosis. As a result, too often, dementia is diagnosed late, limiting access to support, treatment, and opportunities to plan ahead. For many across the UK, getting that diagnosis remains a major challenge - one that it will take society, researchers and governments working together to fix.
"The launch of the ADAPT trial - part of the Blood Biomarker Challenge collaboration - marks a critical step towards that. Blood tests could offer a faster and more accessible route to diagnosis. 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."
Dr Sheona Scales, Director of Research at Alzheimer's Research UK, added: "Today, one in three people with dementia do not have a diagnosis. The ADAPT trial is an important opportunity to change this and transform the way dementia is diagnosed across the UK. It shows how sustained investment in research is leading to breakthroughs in dementia."
A member of the ADAPT Patient and Public Involvement (PPI) group, Michael White, 75, who cares for his wife Kathryn, said: "We all knew there was something serious, but the medical professionals couldn't find it. It took two and a half years to get a diagnosis. 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."
Kathryn White, 74, added: "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."
