A simple blood test can detect Alzheimer’s Disease up to 15 years before symptoms begin, paving the way for a national screening programme.
A major trial found the test – which is already commercially available – was as accurate as the current gold standard for diagnosing Alzheimer’s Disease.
For the first time, doctors were able to categorise a person’s dementia chances as ‘likely’, ‘intermediate’ or ‘unlikely’ from a blood test – ruling out the need for further invasive procedures.
Experts said it will ‘revolutionise’ diagnosis, making Alzheimer’s as easy to test for as routine health conditions such as high cholesterol.
A new blood test for Alzheimer’s is so simple experts say patients could expect results within ‘days’, rather than the years it currently takes to get a diagnosis (stock image)
Patients could expect results within ‘days’ of visiting their GP, rather than the years it currently takes to get a diagnosis.
This could also have ‘huge implications’ for future treatments, removing diagnosis barriers such as long waits for spinal taps or brain scans and speeding up trials.
It could also pave the way for the screening of over-50s, once more effective treatments become available.
Made by diagnostics company ALZpath, it was found to be 97 per cent accurate at detecting traces of tau, linked to developing Alzheimer’s Disease during the eight-year trials.
Swedish researchers found the test – which measures levels of p-tau217 in the blood – corresponded to levels of amyloid and tau proteins seen in brain scans and lumbar punctures.
The higher the levels of this leaked brain protein in the blood, the more likely or advanced the Alzheimer’s Disease was in the in tests involving 786 people.
With breakthrough treatments such as donanemab and lecanemab on the horizon, experts say it is vital to have a quick and reliable diagnosis, when drugs could be most effective.
Professor David Curtis, of the UCL Genetics Institute, University College London (UCL), said this was effectively ‘one half of the solution,’ as the world awaits effective treatments.
He said: ‘This could potentially have huge implications. Everybody over 50 could be routinely screened every few years, in much the same way as they are now screened for high cholesterol.
‘It is possible that currently available treatments for Alzheimer’s disease would work better in those diagnosed early in this way.
‘However, I think the real hope is that better treatments can also be developed.
‘The combination of a simple screening test with an effective treatment for Alzheimer’s disease would have a dramatic impact for individuals and for society.’
Around 900,000 people in the UK live with dementia – with Alzheimer’s the most common form.
The growing ageing population means that numbers are expected to rise to 1.6 million by 2040, making a cheap screening tool vital to get to grips with the challenge.
Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country’s biggest killer.
While previous blood tests have shown promise, these findings have caused particular excitement given the high accuracy levels, large study size and because the test already exists.
It is also the first time a blood test has been found to be at least as good as a painful lumbar puncture, or spinal tap for detecting elevated levels of the tau protein, according to the findings published in JAMA Neurology.
From 1906 when clinical psychiatrist Alois Alzheimer first reported a ‘severe disease of the cerebral cortex’ to uncovering the mechanics of the disease in the 1980s-90s to the recent ‘breakthrough’ drug lecanemab, scientists have spent over a century trying to grapple with the brutal disease that robs people of their cognition and independence
Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier.
Changes in humour and swearing more are all signs of Alzheimer’s and frontotemporal dementia (FTD) a type of dementia that causes problems with behaviour and language. According to experts bad parking, and dressing scruffy are also signs of the memory-robbing disease. Graphic shows: Six signs of Alzheimer’s disease
The results mean the inexpensive tests – priced at around £150 – could also be used to monitor a patient’s condition, allowing more tailored trials or treatment in future.
Dr Richard Oakley, associate director of research and innovation at the Alzheimer’s Society, said: ‘This study is a hugely welcome step in the right direction as it shows that blood tests can be just as accurate as more invasive and expensive tests at predicting if someone has features of Alzheimer’s disease in their brain.
‘Furthermore, it suggests results from these tests could be clear enough to not require further follow-up investigations for some people living with Alzheimer’s disease, which could speed up the diagnosis pathway significantly in future.
‘However, we still need to see more research across different communities to understand how effective these blood tests are across everyone who lives with Alzheimer’s disease.’
Officially classed as a medical device, the tests would need regulatory approval in the UK before any widespread rollout.
But it could form part of NHS trials starting this month looking to roll out an effective blood tests for Alzheimer’s within the next five years.
Private healthcare providers may start offering the test sooner based on the findings by the University of Gothenburg researchers, allowing people to pay for tests before they become routine, experts suggest.
At present, the only ways to definitively diagnose Alzheimer’s are through expensive brain scans or lumbar punctures, which involve taking a fluid sample from the patient’s spinal cord.
A lack of diagnostic capacity and long waiting lists mean only 2 per cent of cases are diagnosed this way, with patients facing wait of up to four years meaning around one in four die before any formal diagnosis is made.
With breakthrough treatments such as donanemab and lecanemab on the horizon, experts say it is vital to have a quick and reliable diagnosis, when drugs could be most effective.
Dr Sheona Scales, director of research at Alzheimer’s Research UK, said: ‘This study suggests that measuring levels of a protein called p-tau217 in the blood could be as accurate as currently used lumbar punctures for detecting the biological hallmarks of Alzheimer’s disease, and superior to a range of other tests currently under development.
‘This adds to a growing body of evidence that this particular test has huge potential to revolutionise diagnosis for people with suspected Alzheimer’s.’
