"The holy grail is to try and have a test that ... will not involve imaging, because when you see something with images it is perhaps too late," Prof Moscato said.
He said the test could be used to screen the wider population, or when people presented to medical appointments with mild cognitive impairment.
Prof Moscato said the test could be useful to determine whether such an impairment was likely to progress to Alzheimer's disease.
People with mild cognitive impairment did not necessarily develop Alzheimer's, Prof Moscato said. Some maintained that level of functioning or progressed to another form of dementia.
He said the test, which analyses proteins in the blood, increased in accuracy when used with a second test done one year later to examine the change in protein levels.
Prof Moscato said if biological markers for Alzheimer's were detected early it would allow people to make lifestyle changes, such as more exercise.
Alzheimer's Australia national research manager Dr Chris Hatherly said it could also help advance research on medical treatments to delay or reverse the disease.
"This is an important new development in the global effort to find simple, reliable and cost-effective measures to identify people with the earliest stages of dementia," Dr Hatherly said.
The research was published in the PLoS (Public Library of Science) ONE journal this week.
- AAP
