Alzheimer's blood test can accurately pick up early symptoms
Experts from the Mayo Clinic in the US have provided further evidence that blood tests can work to accurately diagnose dementia, by examining two proteins in blood plasma.
These proteins – amyloid beta 42/40 and p-tau217 – are associated with amyloid plaque build-up, which is a hallmark of Alzheimer's disease.
Researchers found the blood test was highly accurate, with 95% sensitivity, which means it was 95% accurate in picking up people with memory problems, with very few cases missed.
It was also 82% for specificity, which means it was also highly accurate in ruling out people without dementia.
The study was carried out on more than 500 people in an outpatient memory clinic, meaning it is real-world data.
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.
'Our study found that blood testing affirmed the diagnosis of Alzheimer's disease with 95% sensitivity and 82% specificity,' he said.
'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.
"This study shows how blood tests are making diagnosis of Alzheimer's disease quicker, easier and more accessible than ever before in a real-world setting," he added.
"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."
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