The blood test, currently only available for research- related purposes, measures a specific peptide to inform if a patient has the very earliest stages of Alzheimer's.
The test developed and validated by scientists from Japan and Australia could speed up the pace of Alzheimer's disease drug trials.
"In the first instance, however, it will be an invaluable tool in increasing the speed of screening potential patients for new drug trials," said Masters, who co-led the research published in the journal Nature.
Progress in developing new therapeutic strategies for Alzheimer's disease has been disappointingly slow, researchers said.
None of the three drugs currently on the market treat the underlying disease. New drugs are urgently required, and the only way to do that is to speed up the whole process, they said.
"That requires trials with rigorous and economical patient selection, to avoid recruiting patients who may not even have Alzheimer's disease. Due to the long time-spans involved, pharmaceutical companies require accurate predictions of who is most at risk," said Masters.
The process starts silently about 30 years before any outward signs of dementia.
Current tests for beta-amyloid are expensive, invasive and include brain scans with radioactive tracers, or analysing spinal fluid taken via a lumbar puncture.
Diagnosis is usually made without these tools, rather by assessing a patient's range of symptoms.
The new test was the result of an extensive international collaboration. The key technology, known as IP-MS, was developed by Shimadzu Corporation in Japan.
Blood samples from patients in a large study from the Japanese National Center for Geriatrics and Gerontology (NCGG) were analysed to identify the relevant peptides.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)