Researchers are hopeful that a blood test that can predict the risk of dementia more than a decade before diagnosis may one day be used as a screening tool in the NHS.
The blood test looks for changes in certain proteins in the blood and the scientists behind it say it could predict dementia up to 15 years before the condition is formally diagnosed in patients.
Barriers to early diagnosis are seen as a major obstacle to new game-changing treatments currently being trialled for Alzheimer’s, and scientists believe blood tests may go some way to speeding up the process.
The researchers from the University of Warwick and Fudan University in China described their findings, published in the journal Nature Aging, as a “breakthrough”.
Professor Jianfeng Feng, from the University of Warwick’s department of computer science, said this test “could be seamlessly integrated into the NHS and used as a screening tool by GPs”.
What did the study find?
The researchers identified 11 proteins that they say are more than 90 per cent accurate at predicting future dementia.
These proteins, found in the liquid component of blood known as the plasma, are markers for the biological changes that happen in people who have dementia or Alzheimer’s disease.
One such protein – known as GFAP – has previously been identified as a potential biomarker in smaller studies.
How many people could benefit?
There are more than 944,000 people in the UK who have dementia, which is expected to rise to more than a million by 2030.
The researchers said that an early diagnosis is critical for those with the condition as there are new drugs that can slow progression of the disease if detected early enough.
Two new drugs – lecanemab and donanemab – have been shown in trials to slow “clinical decline” in Alzheimer’s patients by up to 27 per cent and 35 per cent, respectively.
According to Alzheimer’s Research UK, between 20,000 and 40,000 people a year in the UK could benefit from the new drugs.
But due to significant shortages of staff and equipment, the NHS only has the capacity to diagnose and treat about 2,000 of those patients, according to Alzheimer’s Research UK.
Are other blood tests available?
Warwick’s findings are the latest in a growing body of trial evidence from researchers around the world who have been working to develop a blood test that could detect Alzheimer’s disease long before symptoms emerge and enable early treatments.
Trial results published last month found another 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.
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.
When could these tests be available on the NHS?
Pilots of the most promising blood tests could begin in the NHS in less than five years, before being rolled out more widely within the health service by 2028, Alzheimer’s Research UK said last year.
While these tests would not give a final diagnosis, they would identify people with high levels of amyloid, a protein that builds up in the brain and plays a central role in the development of the disease. However, there are hurdles to overcome before they become routine in the health service.
“Blood tests could unlock early diagnosis and are showing great promise, but so far, none have been validated for use in the UK,” said Dr Sheona Scales, Director of Research at Alzheimer’s Research UK.
“We have seen some fantastic progress in the development of blood tests for Alzheimer’s over the last few months.
“This new study adds to the growing body of evidence that looking at levels of certain proteins in the blood of healthy people could accurately predict dementia before symptoms develop. Further studies are needed to understand how these tests and predictive models work with data from more diverse populations.”
Although the researchers behind the latest study said early screening “holds immense significance in pinpointing dementia risks”, Dr Scales pointed out: the key proteins hallmarks of Alzheimer’s disease – amyloid and tau – were not included in the analysis.
“So we don’t know how these proteins would affect the prediction model. And even when tests show promise in studies like this, they still need to go through regulatory approval before they can be used in a healthcare setting,” she said.
How significant are these findings?
For the study, thought to be the largest of its kind, the researchers looked at data from more than 50,000 healthy people from UK Biobank, which holds medical and lifestyle records of more than half a million Britons.
They analysed the blood samples from this group collected between 2006 and 2010. Over a follow-up period of 10 to 15 years, more than 1,400 people went on to develop dementia.
By analysing more than 1,400 different proteins in the blood and using artificial intelligence, the researchers found 11 proteins that could accurately predict dementia up to 15 years before diagnosis.
Dr Richard Oakley, associate director of research and innovation at Alzheimer’s Society, said: “This research looked at proteins in the blood of healthy individuals and followed them up 15 years later and found a common set of proteins in those that went on to develop dementia.
“It’s very early days and lots more work is needed but this could lay the groundwork for the early prediction of dementia and teach us more about how to provide an early and accurate diagnosis. What we need now are blood tests that work in a real-world setting and that can accurately diagnose dementia when someone is starting to show symptoms.
“This is why we’re working with Alzheimer’s Research UK on the Blood Biomarker Challenge which will revolutionise the way dementia is diagnosed. The project, which is possible thanks to £5m in funding raised by players of People’s Postcode Lottery, will gather the information needed to introduce a blood test for dementia into UK healthcare systems.”
'President Musk' is flexing his muscles and revealing how weak Trump is