Alpha-synuclein is a 140 amino acid protein that is abundantly expressed in the nervous system and genetically linked to Parkinson’s disease (PD). It is thought to maintain synaptic integrity and normal cellular homeostasis through synaptic vesicle recycling and neurotransmitter release modulation. While native α-synuclein is unfolded, it has a propensity to form toxic soluble oligomers (i.e., protofibrils) that ultimately aggregate into insoluble fibrils known as Lewy bodies (LBs). Aberrant α-synuclein pathology is prevalent among neurological samples from patients with α-synuclein-related conditions, commonly referred to as “synucleinopathies.” These disorders include PD, dementia with LBs (DLB), and multiple-system atrophy (MSA). Alpha-synuclein has been detected in several biological matrices, such as cerebrospinal fluid (CSF), serum, plasma, and whole blood. Biomarkers that can effectively detect early or pre-symptomatic disease and distinguish PD incidence from other neurodegenerative conditions are of high interest. The MSD Human α-Synuclein Kit can be used to measure α-synuclein in human CSF and serum.