A major clinical trial exploring whether a simple blood test could transform the diagnosis of dementia has begun at Gloucestershire Health and Care NHS Foundation Trust.
The site is among around 20 NHS centres across the UK taking part in the ADAPT trial, a national study led by researchers at University College London (UCL). The trial will investigate whether a blood test can diagnose Alzheimer’s disease earlier and more accurately than current methods used in NHS memory clinics.
The study forms part of the multi-million-pound Blood Biomarker Challenge, led by the Alzheimer’s Society and Alzheimer’s Research UK with support from funding raised by players of People’s Postcode Lottery, the National Institute for Health and Care Research, and Gates Ventures. The initiative aims to bring blood tests for dementia into routine NHS use by 2029.
Recruitment for the trial began at Essex Partnership University NHS Foundation Trust in August 2025, with more sites now opening nationwide. More than 1,100 participants are expected to take part across the UK.
Researchers say improving the speed and accuracy of dementia diagnosis is crucial, as it allows people to access treatment earlier, plan for the future and receive appropriate care and support. However, current diagnostic processes often rely on memory assessments, brain scans or lumbar punctures, which can be slow, invasive and costly.
As a result, many people face lengthy waits for diagnosis or remain undiagnosed.
The ADAPT trial aims to assess whether a blood test could offer a faster, simpler and more accessible alternative. People referred to NHS memory clinics for the first time due to concerns about memory and thinking will be invited to participate.
All participants will undergo the standard diagnostic assessments currently used in the NHS. Half will receive the results of the blood test early in the diagnostic process, while the remaining participants will receive the results later.
Researchers will then assess whether earlier access to blood test results can help speed up diagnosis, guide decisions about further investigations and improve quality of life for people living with dementia. The study will also examine the potential impact on healthcare costs and outcomes for different groups of patients.
The test measures a biomarker known as p-tau217, which reflects the build-up of amyloid and tau proteins in the brain — two hallmarks of Alzheimer’s disease. Evidence suggests the test can detect these changes with accuracy comparable to established methods such as PET scans and lumbar punctures, but in a way that is less invasive and potentially more widely available.
Currently, only around two per cent of people with Alzheimer’s disease have access to these specialist tests.
Dr Ashvini Keshavan, senior clinical research fellow and honorary consultant neurologist at the Dementia Research Centre at UCL Queen Square Institute of Neurology and co-lead of the ADAPT trial, said Gloucestershire memory clinics playing a role in the study marked an important step forward.
“We’re proud that Gloucestershire memory clinics will be part of this important national trial and thrilled to welcome participants as sites open across the country,” she said.
“This is 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 that provides comparable information to gold-standard diagnostic tests but is far more accessible and cost-effective. This landmark trial will provide the vital evidence needed to integrate blood tests into routine clinical practice across the NHS.”
Laura Chow, head of charities at People’s Postcode Lottery, said the trial could mark a turning point in dementia care.
“We are delighted to see the groundbreaking ADAPT blood test trial for Alzheimer’s disease now underway nationwide,” she said. “This marks a pivotal moment in the quest to improve dementia care and highlights the immense value of funding raised by players of People’s Postcode Lottery.”
Participants in the trial will be recruited through NHS memory services and will include people from a wide range of geographic, ethnic and socioeconomic backgrounds, as well as those living with other health conditions.
Researchers say this approach will help ensure the findings are representative and relevant to the wider population.
The READ-OUT study, another project within the Blood Biomarker Challenge, has also begun recruiting participants in recent months. It aims to enrol more than 3,100 people across 33 Dementias Platform UK sites nationwide.