Phosphorylated Alpha-Synuclein in Red Blood Cells as a Potential Diagnostic Biomarker for Multiple System Atrophy: A Pilot Study

Table 2

ELISA spike-and-recovery assessments of pS-α-syn in RBC lysates.

Sample	No spike (0 μg/ml)	Low spike (1.5 μg/ml)	Medium spike (3.0 μg/ml)	High spike (4.5 μg/ml)
0.01 M PBS	0	1.70	2.80	4.00
RBC1	1.35	1.45	2.38	3.81
RBC2	1.13	1.56	2.87	3.65
RBC3	2.07	1.41	2.57	3.98
RBC4	1.64	1.59	2.39	3.82
RBC5	1.91	1.46	2.48	3.96
RBC6	2.23	1.48	2.46	3.83
RBC7	1.86	1.51	2.72	3.75
RBC8	1.77	1.49	2.59	3.77
RBC9	1.42	1.47	2.36	3.98

Samples were assayed by adding 100 μl of sample and a different spike stock solution to yield the intended 0, 1.5, 3, or 4.5 μg/ml spike concentration. Values reported for spike samples reflect a subtraction of the endogenous (no spike) values. Recoveries for spiked test samples were calculated by comparison to the measured recovery of spiked diluent. All values represent the average of three replications.