A blood test to detect Parkinson's disease has been developed by Australian researchers, a breakthrough which will allow for earlier intervention and treatment of the debilitating condition.
Currently there is no definitive test to diagnose Parkinson's disease and patients have to rely on a neurological exam, which can be problematic because results are often open to interpretation. 
"This is a really exciting discovery," said microbiologist Paul Fisher, who led the research team from La Trobe University.
Human trials of the test, which picks up on a key biological marker found in the blood, have delivered a 95 per cent accuracy rate.
The biological clue the test is looking for relates to the blood's "appetite" for oxygen. A patient with Parkinson's disease has white blood cells which consume oxygen four times faster than normal healthy cells.
"It's a very dramatic difference, which is why it's useful as a biomarker," Professor Fisher said.
A definitive diagnostic test will enable early intervention, limiting the number of brain cells destroyed as the disease takes hold. This is crucial to managing the disease, which affects about 80,000 Australians. As there is no cure, slowing the rate of deterioration can have a dramatic impact on a patient's quality of life and mobility.
Karyn Spilberg, who was diagnosed with young-onset Parkinson's disease in 2002 as a 44-year-old, described the results as a breakthrough.
Unlike most patients Mrs Spilberg's diagnosis was relatively quick, bringing with it a sense of certainty and an ability to intervene early.
"Usually people take a long time to get diagnosed because there's no testing, until now," she said. "People can go for years and years without knowing what is wrong with them ... which is why this test is such a big breakthrough."
Mrs Spilberg, a Parkinson's Victoria board member, said early diagnosis would minimise stress and uncertainty, allowing people to also benefit from earlier treatment and lifestyle interventions, such as exercise and healthy eating.
The human trials on 38 patients, 29 of them with Parkinson's, included people who had been diagnosed between two and 30 years earlier.
Professor Fisher said the results were the same, regardless of how much time had passed since diagnosis. This suggests the potential for diagnosis before symptoms present.
"The results were completely stable," he said. "It suggests that if you were to project back in time, you might even be able to pick it up even before any current diagnosis was possible."
The blood test could potentially pick up other neurodegenerative conditions such as Alzheimer's, Professor Fisher said.
The La Trobe University research team, including Sarah Annesley and Danuta Loesch-Mdzewska, have received a significant funding boost to continue the research - half from the Michael J Fox Foundation in the United States and half from Australian partner organisation Shake It Up.
The $640,000 grant will enable a second round of human trials to begin in Melbourne.
Actor Michael J. Fox was diagnosed with young-onset Parkinson's disease in 1991, seven years before going public with the news. The Michael J Fox Foundation was established in 2000 and since then has raised more than US$450 million for Parkinson's disease research.