A new blood test to diagnose Parkinson's disease (PD) before symptoms appear has been developed. The test measures the blood concentration of a brain-secreted protein called 'alpha-synuclein', which is found to be low in PD patients.

"Currently there is no specific PD diagnostic test so doctors rely on their observations to make a diagnosis, which means some patients may not be prescribed the most suitable medication and around 15% of those diagnosed may actually be suffering from something else," Prof Horne said.

A large-scale study is not being conducted to determine the effectiveness of the test, to discover whether it is applicable for all types of PD, and to find out if it can measure the rate of progression and severity of the disease. The test is also being modified to make it quicker and cheaper to make it more accessible to individuals who are at risk of developing PD.

More details from the Howard Florey Institute.