Blood test for Alzheimer’s could soon be available on the NHS

A new blood test for Alzheimer’s disease has been found to accurately detect early symptoms of the illness, according to new research.

Experts from the Mayo Clinic in the US examined two proteins in blood plasma – amyloid beta 42/40 and p-tau217 – which are associated with amyloid plaque build-up, a hallmark of Alzheimer’s disease, to provide further evidence that blood tests can accurately diagnose dementia.

The study, which was carried out on more than 500 people in an outpatient memory clinic, found the blood test was highly accurate, with 95 per cent sensitivity.

That means it was 95 per cent accurate in picking up people with memory problems, with very few cases missed.

It was also 82 per cent for specificity, meaning it was also highly accurate in ruling out people without dementia.

The blood test has already been approved by the Food and Drug Administration regulator in the US.

Dr Gregg Day, who led the study in the Alzheimer’s and Dementia journal, said the test was as good as more invasive tests currently in use.

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“When performed in the outpatient clinical setting, this is similar to the accuracy of cerebrospinal fluid biomarkers of the disease and is much more convenient and cost-effective.”

Overall, researchers found that p-tau217 levels were higher in patients with Alzheimer’s disease versus those without the disease.

Dr Day said the next steps in the research were to evaluate blood-based testing in more diverse patient populations and people with early Alzheimer’s who show no cognitive symptoms.

Dr Richard Oakley, associate director for research and innovation at the Alzheimer’s Society in the UK, said the results “suggest this test is very accurate” and could be used alongside other tests and observations from a trained health professional.

“While focused on Alzheimer’s disease, the test was evaluated in people with other types of dementias too, showing that it may help with differentiate causes of cognitive decline – though more research in diverse groups of individuals and in community-based setting is still needed.

“Currently diagnosis options in the UK are often slow, expensive and can be invasive, meaning thousands miss out on the benefits one can bring.

“It’s great to see blood tests like this approved for clinical use in the US – we hope to see the same in the NHS, which is why we’re part of the Blood Biomarker Challenge.”

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The Blood Biomarker Challenge is a multi-million-pound research programme supported by the Alzheimer’s Society, Alzheimer’s Research UK and the National Institute for Health and Care Research.

Its goal is to bring blood tests for dementia diagnosis to the NHS by 2029.

Dr Julia Dudley, head of research at Alzheimer’s Research UK, said: “We urgently need to improve how we diagnose dementia and it’s great to see international research working towards this goal.

“Blood tests in this study look at p-tau217 and amyloid beta 42/40, and showed the tests offered high accuracy in confirming Alzheimer’s disease.

“This study adds to the growing evidence that blood tests can detect the diseases that cause dementia in people with early memory and thinking problems.

“An important point to consider is that people taking part in research don’t always reflect the full diversity of those affected by dementia, who might have additional conditions or other characteristics.

“That is why work is needed to understand whether these blood tests work in a real-world setting.”