Researchers from Washington University School of Medicine have developed a test that when combined with age and genetic risk factor, could help detect the brain changes of early Alzheimer’s disease.

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.

“Right now we screen people for clinical trials with brain scans, which is time-consuming and expensive, and enrolling participants takes years,” said senior author Randall J. Bateman.

“But with a blood test, we could potentially screen thousands of people a month. That means we can more efficiently enroll participants in clinical trials, which will help us find treatments faster, and could have an enormous impact on the cost of the disease as well as the human suffering that goes with it.”

Bateman also explained that “If you want to screen an asymptomatic population for a prevention trial, you would have to screen, say, 10,000 people just to get 1,500 or 2,000 that would qualify,” before going on to say that “Reducing the number of PET scans could enable us to conduct twice as many clinical trials for the same amount of time and money. It’s not the $4,000 per PET scan that we’re worried about. It’s the millions of patients that are suffering while we don’t have a treatment. If we can run these trials faster, that will get us closer to ending this disease.”

The Alzheimer’s pipeline is an area of frequent failures, making it a space of high unmet need.