Alzheimer's is strongly linked to the build-up of clumps of toxic beta-amyloid peptide, a protein building block, in the brain.
The same technology was successfully used to treat more than 1,35,000 patients worldwide with Parkinson's disease, the researchers said.
The gold standard now for testing for the presence of amyloid beta are costly PET scans, or analysing spinal fluid collected via invasive lumbar punctures.
At the moment there is no treatment to change the course of Alzheimer's, so any test would have limited use for patients. The scientists who developed this blood test have shown that by analyzing the ratios of types of amyloid fragments in the blood, they could predict levels of the protein in the brain.
The team trialed the test on 121 patients from Japan and 252 from Australia with varying levels of health, ranging from healthy to mild cognitive impairments or Alzheimer's disease. "In the first instance, however, it will be an invaluable tool in increasing the speed of screening potential patients for new drug trials", Laureate Professor Colin Masters from Melbourne's Florey Institute of Neuroscience and Mental Health said.
Up to 40 per cent of people over 70 years old are at risk of Alzheimer's disease due to the beta-amyloid in their brains, according to Dementia Australia.
One method is to look for a toxic protein - called amyloid beta - that builds up in the brain during the disease.
Scientists not directly involved in the study said it made an important step, but now needed to be replicated. "None of the three drugs now on the market treat the underlying disease", Masters said in a statement. "Not everyone with amyloid in their brains will turn out to have dementia, and not everyone who has dementia will be found to have amyloid in their brains".
The study found the test was capable of detecting the peptides in people at each stage of disease progression; a process that typically takes 30 years, from preclinical to full-blown Alzheimer's disease, Professor Masters said. Alzheimer's research had suffered monumental setbacks in the past few years, with none of the three drugs now available effective at treating the underlying disease. Following on from that, a simple way to screen for the disease, years before any symptoms actually appear, will help patients apply countermeasures to battle the deleterious effect of these amyloid beta concentrations.
It's still early days for the research with more testing necessary before the blood test would be deployed into practice for the general public, but a more immediate use could be in evaluating participants for Alzheimer's related clinical trials.