Fig. 4.

Each fragment of CSF p217 + tau is elevated in AD. CSF from 20 amyloid positive (CSF Aβ42 < 600 pg/ml; red bars) and 20 amyloid negative (CSF Aβ42 > 600 pg/ml; blue bars) subjects (10 CDR 0 and 10 CDR 0.5 in each group) was fractionated by rpHPLC and measured with (A) p217 + tau long assay (PT3×HT43), (B) p217 + tau short assay (PT3×PT82), and (C) t-tau assay (HT7×PT82). D) The sum of all peaks in the p217 + tau long assay reveals higher signal in AD (red bar) versus amyloid negative subjects (green or blue bars). ARAD, asymptomatic at risk of developing AD.