Figure 1.

The effects of blood contamination on DJ-1 or α-synuclein levels in CSF. CSF DJ-1 (A) and α-synuclein (SNCA) (B) levels were measured in individual control (CTL) and disease (Alzheimer’s disease, AD; Parkinson’s disease, PD) samples by Luminex, while the haemoglobin levels were measured using an ELISA kit. The haemoglobin variable was log transformed (log10) for the correlation study due to its positively skewed distribution. A fit line is shown for all the samples tested. A positive correlation between haemoglobin and DJ-1 (C) or α-synuclein (D) levels was also observed in whole blood serially diluted in the Luminex assay diluent (0.1% bovine serum albumin/phosphate buffered saline).