The test, which looks for cell damage associated with the disease, is years away from being commercially available.

If its reliability is confirmed in future trials, the test would allow doctors to diagnose the condition earlier and start therapies sooner, before nervous system damage worsens, the researchers said. 

“Currently, Parkinson’s disease is diagnosed largely based on symptoms, when patients already have significant neurological damage,” said study leader Laurie Sanders of Duke School of Medicine in Durham, North Carolina. 

Presently, drugs for Parkinson’s disease only help control symptoms.

Sanders said she hopes that along with diagnosing Parkinson’s, the new test will help identify drugs that can reverse or halt mitochondrial DNA damage and the disease process, as well as patients who could benefit from those drugs.