A blood test that can diagnose Alzheimer's Disease two decades before symptoms appear has been trialled.
The easy test charts levels of of a protein in the blood associated with the condition and was found to be 94 per cent accurate.
Scientists have been searching for an accurate test that will help diagnose dementia before the onset of symptoms, which is key to controlling the condition.
Once they develop irreparable damage has already been done to the brain.
The test, developed by US researchers, could be available to doctors within “a few years”.
They say it was so accurate in the trial of 158 patients that it may be better than the current “gold standard” test – a time-consuming and expensive PET brain scan, MirrorOnline reports.
One person is diagnosed with dementia every three minutes in Britain. Before they develop memory loss and confusion, clumps of the protein amyloid beta build up in their brains.
Research to find a drug that could halt the progress of dementia has hit a dead end.
The new test could be used to recruit thousands of people on to clinical trials to make this breakthrough. Author Prof Randall Bateman, of Washington University, said: “If we can run these trials faster, that will get us closer to ending this disease.”
It is hoped people with amyloid beta build-up could have drugs tested on them to prevent cell damage.
Researchers reported they can measure levels of the protein in the blood and use them to predict whether amyloid beta has accumulated.
When combined with two other major Alzheimer’s risk factors – age and the presence of the genetic variant APOE4 – people with early brain changes were identified with 94 per cent accuracy.
Clinical trials of drug candidates have been hampered by the difficulty of identifying participants who have Alzheimer’s brain changes but no symptoms. Prof Bateman added: “Reducing the number of PET scans could enable us to conduct twice as many trials for the same amount of time and money.
“It’s not the cost of PET scans we’re worried about. It’s the millions of patients who are suffering while we don’t have a treatment.”
There are 850,000 people with dementia in the UK which is set to rise to more than a million by 2025. It is predicted to top two million by 2051.
Dr James Pickett, research head at the Alzheimer’s Society, said: “A simple blood test that can detect early brain changes leading to dementia would revolutionise the search for new treatments.”
