Abstract: Embodiments of the invention include a system and method of using biomarkers in the diagnosis of Parkinson's disease. A subject can be screened for Parkinson's disease based on altered expression of one or more biomarkers in blood, plasma or saliva from the subject. Embodiments include 18 specific mRNA biomarkers to screen or distinguish healthy individuals from individuals affected with Parkinson's disease. Embodiments also include 33 specific protein biomarkers to screen or distinguish healthy individuals from individuals affected with Parkinson's disease. The biomarkers can also be used to determine the prognosis of a subject with the disease and identify early-onset and/or asymptomatic Parkinson's disease.