American researchers say they can accurately identify people on track to develop Alzheimer's disease, BBC reports.

US scientists were able to use levels of a protein in the blood to help predict its build-up in the brain.

The new method gives indications about the disease before symptoms appear.

Data from the research were published in Neurology magazine.

Levels of the protein amyloid beta

Researchers from Washington University School of Medicine, in St Louis, Missouri, measured levels of the protein amyloid beta in the blood of 158 adults aged over 50 to see if this matched levels found in brain scans.

It did, but only 88% of the time. When the researchers combined this information with two other risk factors for the disease - an age of over 65 and people with a genetic variant called APOE4, which at least triples the risk of the disease - the accuracy of the blood test improved to 94%.

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We can more efficiently enrol 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", senior study author Randall J Bateman, professor of neurology, said.

Participants in trials must have early Alzheimer's brain changes - such as build-up of amyloid - but no cognitive problems as yet.

Read the whole study HERE