Blood test is 94 per cent accurate at identifying early Alzheimer's disease

Up to two decades before people develop the characteristic memory loss and confusion of Alzheimer's disease, damaging clumps of protein start to build up in their brains.

Now, a blood test to detect such early brain changes has moved one step closer to clinical use.

Researchers from Washington University School of Medicine in St. Louis report that they can measure levels of the Alzheimer's protein amyloid beta in the blood and use such levels to predict whether the protein has accumulated in the brain.

When blood amyloid levels are combined with two other major Alzheimer's risk factors - age and the presence of the genetic variant APOE4 - people with early Alzheimer's brain changes can be identified with 94 per cent accuracy, the study found.

The findings, published on 1 August in the journal Neurology, represent another step toward a blood test to identify people on track to develop Alzheimer's before symptoms arise.
Dr James Pickett, Head of Research at Alzheimer’s Society, said:

A simple blood test that can detect the early brain changes leading to dementia would really revolutionise the search for new treatments, and our funded research has identified changes in the blood of those in the earliest stages of Alzheimer’s. 

'While the idea of an Alzheimer’s blood test feels like it has been around for decades, advances in technology over the last couple of years mean that it is now a becoming a reality, and fast. This is an incredibly exciting area of progress in dementia research. 

'But it’s important to note this isn’t a blood test for dementia – it tells us that amyloid deposits are in the brain, which are a hallmark of Alzheimer’s disease, but are also found in healthy older people too. This test will speed up dementia research by identifying those at risk of Alzheimer’s who might be suitable for clinical trials aimed at preventing or delaying the development of dementia. In the meantime, we're eagerly awaiting the results of larger studies to validate this blood test.'