Blood test indicates Alzheimer’s brain changes

20 July 2017

Researchers presenting findings at the Alzheimer’s Association International Conference 2017 have found that a blood test could help indicate the presence of the hallmark Alzheimer’s protein, amyloid, in the brain.

Alzheimer’s disease involves a number of different biological processes, but scientists believe that a central change is the build-up of the amyloid protein. Current methods for detecting amyloid in the brain involve using expensive PET scans or analysing samples of spinal fluid that have to be collected through a lumbar puncture. A reliable blood test for amyloid in the brain could be a cheaper, more convenient alternative that could have important uses in research studies and potentially in supporting Alzheimer’s diagnoses.

The researchers in this study collected blood samples from people with and without Alzheimer’s disease. Each participant had either an amyloid PET scan or a lumbar puncture to assess levels of amyloid in the brain. They studied specific characteristics of amyloid in the blood to see if they indicated the presence of the protein in the brain. Their results show that amyloid in the blood is affected by amyloid in the brain, and highlights the potential of blood tests for brain amyloid.

Dr David Reynolds, Chief Scientific Officer of Alzheimer’s Research UK, said:

“The brain is locked away from the rest of the body in layers of protection that keep it safe from damage and infection, but that makes it very difficult to study. This research doesn’t present a convenient way to test for amyloid in the brain, but it helps scientists better understand the relationship between what we can measure in the blood and what’s happening in the brain. While a test for amyloid is not the same as a test for Alzheimer’s disease, a reliable blood test for this protein would be extremely valuable to researchers and could have important future applications both in research and in supporting decisions around diagnosis.

“One significant challenge in taking blood tests into the clinic is ensuring they are sensitive enough not to wrongly implicate a diagnosis where there isn’t one, or to give a ‘false positive’ result to those who are healthy. Any potential blood test to inform the diagnosis of a disease like Alzheimer’s would need rigorous testing at a population level to understand it’s value, as well as its limitations for use in the clinic. The development of a blood test for hallmarks of Alzheimer’s would create a step change in our ability to detect and monitor the disease, and is a very important and active area of dementia research.”