Researchers are saying that the test 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, bringing the possibility of detecting brain changes of early Alzheimer’s “one step closer to reality”.
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, a sign that could be used to detect the disease before onset.
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% accuracy, the study found.
The results represent “another step toward a blood test to identify people on track to develop Alzheimer’s before symptoms arise”, and may be even more sensitive than the gold standard – a PET brain scan – at detecting the beginnings of amyloid deposition in the brain.
The blood test could provide a way to efficiently screen for people with early signs of disease so they can participate in clinical trials evaluating whether drugs can prevent Alzheimer’s dementia.