Thousands of Britons to receive cheap Alzheimer's blood tests in landmark NHS trial

Thousands of adults in the United Kingdom will be offered inexpensive blood tests designed to detect Alzheimer’s disease in a landmark clinical trial aimed at speeding diagnosis and widening access to testing.

The trial, led by researchers at University College London, will recruit about 1,100 people across 20 areas of the country who have reported memory or thinking problems to their general practitioner and may be in the early stages of dementia. Half of participants will receive their blood test results after three months, and the other half after 12 months, allowing investigators to assess whether earlier test information changes clinical care and quality of life.

The blood assay measures a protein called phosphorylated tau 217, or p‑tau217, which researchers say indicates the presence of both amyloid and tau pathology in the brain. Accumulations of these proteins in the form of plaques and tangles are associated with the cognitive decline seen in Alzheimer’s disease. Scientists involved in the trial say the blood test provides information comparable to PET brain scans and lumbar punctures but is cheaper and less invasive.

Currently, formal diagnosis of Alzheimer’s in the UK often depends on batteries of cognitive tests, neuroimaging such as PET or MRI scans, or lumbar punctures to sample cerebrospinal fluid. Access to those “gold-standard” diagnostic procedures is limited: researchers on the trial estimate only about 2% of people diagnosed with Alzheimer’s have access to them. Clinicians and investigators say a reliable blood test could widen diagnostic coverage and reduce delays to treatment and support.

Professor Jonathan Schott, professor of neurology at University College London and chief medical officer at Alzheimer’s Research UK, said the trial represents a step toward “revolutionising the way we diagnose dementia.” He said that, after decades of research, the blood test is backed by strong scientific evidence and could be especially important as new treatments that slow cognitive decline become available.

Professor Fiona Carragher, chief policy and research officer at the Alzheimer’s Society, said dementia is often diagnosed late, limiting access to treatment and planning opportunities, and described the trial as “a critical step” toward making diagnosis faster and more accessible. The study is part-funded by the People's Postcode Lottery, according to the research team.

Researchers will collect data on whether receiving earlier test results changes subsequent care pathways, treatment access and patients’ reported quality of life. Recruitment at the first trial site, within Essex Partnership University NHS Foundation Trust, began late last month.

Public health context underscores the potential impact. Current estimates place the number of people living with dementia in the UK at roughly 900,000 to 944,000, and some projections from University College London scientists suggest that figure could rise to about 1.7 million within two decades as the population ages. Alzheimer’s disease accounts for around six in 10 dementia cases. Analyses cited by researchers also indicate a substantial rise in dementia-related deaths in recent years, contributing to calls for improved detection and care strategies.

The trial team said that, beyond earlier diagnosis, a scalable blood test could help triage patients more efficiently in primary care and ensure those with Alzheimer’s pathology are fast-tracked for further assessment and potential therapies. Investigators will monitor how frequently test results lead to changes in referrals, imaging or treatment, and whether early diagnosis affects caregiver burden and patient planning.

Ethical and operational considerations will be tracked as part of the study. Researchers emphasized the importance of clear communication about what a positive or negative blood test means, given the complexities of dementia diagnoses and the range of possible underlying causes for cognitive symptoms.

If the trial shows that routine blood screening is feasible, accurate and improves patient outcomes, clinicians and health services say it could be deployed more widely to address long-standing gaps in dementia diagnosis across the NHS. The research team has framed the study as part of broader efforts to ensure that advances in diagnostic tools and emerging therapies reach people at the stage when interventions are most likely to help.

Recruitment will continue across the 20 sites, with trial investigators set to report interim and final analyses once sufficient follow-up data are available to evaluate clinical and quality-of-life outcomes.