UK researchers have begun testing a groundbreaking blood test that could dramatically speed up and simplify the diagnosis of Alzheimer’s disease. The test, which detects the protein p-tau217—a biomarker strongly linked to the brain changes seen in Alzheimer’s—will be offered to over 1,100 people showing early signs of cognitive decline.
The study, coordinated by University College London (UCL) under the “Blood Biomarker Challenge,” aims to establish whether the test can match or even outperform existing diagnostic tools in a real-world NHS setting. At present, definitive diagnosis typically relies on costly and invasive methods such as PET brain scans or lumbar punctures, procedures available to only about 2% of UK patients.
P-tau217 is especially promising because it signals the presence of both amyloid and tau proteins—hallmarks of Alzheimer’s. Previous lab-based studies suggest the test can correctly identify the disease in roughly 80% of patients with cognitive symptoms. This trial will examine whether using it early in the diagnostic process can improve accuracy and guide treatment decisions more effectively than current practice.
Recruitment began recently at Essex Partnership University NHS Foundation Trust, with 19 more centres expected to join. Participants will include people from a wide range of ethnic, social and health backgrounds to ensure the findings reflect the UK’s diverse population.
Professor Jonathan Schott, UCL neurologist and Chief Medical Officer at Alzheimer’s Research UK, said the blood test delivers information comparable to “gold-standard” tools but is more accessible and affordable. With new drug treatments emerging that may slow memory loss, Schott stressed that early and precise diagnosis is becoming critical to ensure patients benefit.
The trial also responds to a broader problem: many people with dementia in the UK receive a diagnosis late, or have a negative experience of the process. According to Alzheimer’s Society, only one in three patients reports a positive diagnostic experience, and fear of the results is a major barrier to seeking help. This delay often limits access to care, treatment, and planning support.
If successful, the blood test could be incorporated into standard NHS memory assessments within a few years—potentially reshaping how Alzheimer’s and other dementias are detected and managed.
