Laboratory assessments in the course of Parkinson's disease: a clinician's perspective.

Physicians, caregivers and patients themselves must be alert to the onset of and changes in motor and non-motor features during the course of Parkinson's disease (PD). Parallel laboratory routine assessments are necessary because of the evolving impairment of the general health status of the individual. A number of potential biomarkers for the diagnosis of PD are currently under investigation, with diagnosis early in the disease course a particular goal, even before the onset of motor symptoms. The aim of this guideline article is to provide user-friendly, clinical evidence-based recommendations for using laboratory pathological testing for the diagnosis and differential diagnosis of PD, for assessing its time course, and managing complications of long-term dopaminergic therapy and the disabling motor features that develop in the later stages of the disease.