In one aspect, the present disclosure relates to a method for excluding a subject from the need for diagnostic testing for Parkinson's disease (PD). In another aspect, the present disclosure relates to a method for excluding a subject from recruitment into a clinical study for an investigational PD medication. In yet another aspect, the present disclosure relates to a method for screening a subject to determine whether the subject is ruled out as having PD, wherein the subjects who cannot be ruled out are administered a diagnostic test for PD, a treatment for PD, or a combination thereof.