NEFL and amyotrophic lateral sclerosis: Nf-L measurement in plasma samples by MSD using the same starting volume showed the previously described up-regulation of Nf-L in ALS-Fast compared to ALS-Slow and HC in plasma6 (Fig. 3A.1), while in matched DBS elutes, there was a trend for higher expression in ALS-Fast compared to ALS-Slow and HC of the Nf-L/haematocrit ratio which did not reach statistical significance (Fig. 3A.2).