There will be a test of a biomarker which meaningfully correlates with parkinson's progression for at least a signficant subset (>10% of those diagnosed clinically) of people with Parkinson's disease in the US before 2029
examples: Patient has classic non-genetic PD from a clinical diagnosis based on symptoms (rigidity, etc.). There will be a test which they can take which shows the severity of the disease, and which when given repeatedly can be used to measure how much or less the disease has progressed
1,000% too high I'm afraid. So far the available test can diagnose early (alpha synclein assays and datscan) and maybe predict the people most at risk but there's no evidence that they correlate with the progression of the disease yet (unless you really significantly decline, for instance become demented).