A more efficient enzyme-linked immunosorbent assay for measurement of alpha-synuclein in cerebrospinal fluid.

We describe a modification of a previously described assay for the quantification of alpha-synuclein in naive cerebrospinal fluid, which allows for a more efficient quantification of alpha-synuclein. Detection limit of the assay is 3.8 ng/ml and the assay is linear until 300 ng/ml. Inter-assay and intra-assay coefficients of variation are below 15% in a wide range of concentrations. Mean recovery of the assay is 94%. The 95% upper limit of the reference range (p95) in a group of neurological controls above the age of 45 years is 62 ng/ml. This assay can be routinely applied for quantification of alpha-synuclein in cerebrospinal fluid, but not in serum, and this may serve as a possible biomarker for alpha-synucleinopathies such as Parkinson's disease and multiple system atrophy.