The test works by identifying changes in signalling proteins that are used by the brain to communicate to other parts of the body.
The researchers came up with the concept after comparing blood samples from five people diagnosed with Alzheimer's with those from five people free from the disease.
A number of changes to a set of signalling proteins were found in the blood plasma of the Alzheimer's patients. These proteins were used as markers for the alterations to the chemistry of the brain that precede Alzheimer's disease.
The researchers expanded the study to include 259 archived blood samples taken from individuals with symptoms of Alzheimer's.
They developed an analysis procedure to identify if there was a pattern seen in the proteins found in Alzheimer's patients that could be compared with that of people without the disease.
Eighteen proteins were identified that were specific to Alzheimer's.
To test the accuracy of the blood test, the researchers selected 47 people with mild cognitive impairment who had been followed-up for two to six years.
The blood test was performed on samples taken at the beginning of the study.
The test identified 91 per cent of the patients who went on to develop Alzheimer's by the end of the six-year follow-up.
However, the researchers stress the findings of the blood test still need to be confirmed.
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