Blood test may offer fast, accurate and less painful way to diagnose Alzheimer’s
A blood test has been developed to detect Alzheimer’s disease which experts say could revolutionise diagnosis for people with the world’s most common form of dementia.
In research, it has proved as accurate and less painful than existing tests – including a lumbar puncture.
The test measures levels of a protein called p-tau217 – which signals changes in the brain associated with the development of Alzheimer’s that begin up to 15 years before symptoms start.
The study of about 800 people in three countries used the presence of the protein to predict patients likely, intermediate and unlikely to have Alzheimer’s.
The study was led by Dr Nicholas Ashton of the University of Gothenburg and was published in the Jama Neurology journal.
Some people receive diagnosis of Alzheimer’s through a lumbar puncture or PET scan. But there are not enough PET scanners, which means many patients wait years for diagnosis.
Researchers will now study whether their results can be replicated, including in clinics people visit with memory concerns. If successful, experts say the test could be available in three to five years.
“This study is a hugely welcome step in the right direction,” said Dr Richard Oakley, associate director of research and innovation at UK charity the Alzheimer’s Society.
“It shows blood tests can be 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.”
The only way to currently prove that someone has a build-up of the proteins in the brain is to have a lumbar puncture or an amyloid PET scan, which are available in about one in 20 UK National Health Service memory clinics.
Dr Sheona Scales, director of research at the Alzheimer’s Research UK charity, said results suggest the new test was superior to others 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,” she said.
But Dr Scales said a clearer picture is needed of how these types of blood tests perform in real-world healthcare systems.
David Curtis, honorary professor at the Genetics Institute at University College London, said: “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.”
About 139 million people worldwide will be living with dementia by 2050, according to the Alzheimer’s Disease International organisation.