Melbourne researchers are on the brink of developing a blood test to detect Alzheimer's disease potentially years before symptoms appear.

Researchers from Melbourne's La Trobe University have identified abnormalities in the blood  linked to the degenerative condition affecting more than 350,000 Australians.

Molecular biologist Lesley Cheng said doctors could be provided with the definitive diagnostic tool they lack though a simple blood test.

An earlier diagnosis would allow for earlier treatment, which could potentially delay symptoms.

The research team was led by Andrew Hill, and identified 16 abnormalities in the blood of Alzheimer's patients after isolating microRNA, a genetic material that controls gene expression.

MicroRNA is found in concentrated levels in cell secretions called exosomes, which are able to be isolated from blood.  Through analysis of these secretions from Alzheimer's patients and comparing them to healthy people, the differences were able to be pinpointed.

There is currently no single test to identify or diagnose Alzheimer's, with doctors instead relying on a series of neuro-psychological test to form a diagnosis.  These methods can be problematic due to their subjectivity.  The only conclusive diagnosis can be made post-mortem, where brain tissue can be analysed.

Dr Cheng also hopes the blood tests can be used to identify other neurodegenerative diseases, such as Parkinson's disease.

Alzheimer's is the most common form of dementia, affecting about 70 per cent of those with the condition.

Victoria is a leading location for neuroscience research and the development of innovative new therapies and devices.  Built on world class research, outstanding infrastructure and technology platforms, and a vibrant life sciences and devices sector, the state is at the cutting edge of advances in the management of disorders of the brain and central nervous system.