Revolution at the Memory Clinic: Inside UCL’s NHS Trial of a £100 Alzheimer’s Blood Test, the 90% Accuracy Evidence, and What Comes Next
Across 20 NHS memory clinics, University College London has launched ADAPT, a real‑world trial offering more than a thousand people with suspected dementia a low‑cost (~£100) blood test that measures phosphorylated tau at threonine 217 (p‑tau217). The aim is to raise diagnostic accuracy from around 70% to above 90%, speed up time to a confident diagnosis, and extend biomarker confirmation beyond the small minority who currently receive positron emission tomography (PET) or cerebrospinal fluid (CSF) testing. ADAPT will also assess how earlier, objective biomarker results change clinical decisions, downstream testing, and patients’ quality of life. That ambition rests on a strong evidence base. Peer‑reviewed studies in 2024 show plasma p‑tau217 can match or outperform clinically used CSF assays in identifying Alzheimer’s pathology, achieving area under the curve (AUC) values around 0.95–0.98 and diagnostic accuracy near 90% in treatment‑relevant populations. A prospective evaluation in routine primary and secondary care reported similarly high accuracy and, critically, boosted clinicians’ diagnostic performance from approximately 61–73% to about 91% when the blood test informed decision‑making. A complementary framework study provides guidance on when a blood test alone can rule in or rule out Alzheimer’s pathology versus when confirmatory PET/CSF is still warranted. This article examines ADAPT’s design and endpoints, explains the biology and performance of p‑tau217, reviews prospective real‑world data, and outlines how the NHS can implement standardized, equitable blood‑biomarker pathways that minimize invasive testing and prepare services for disease‑modifying therapies.