Fig. 1.
Impact of aliquot size on cerebrospinal fluid (CSF) amyloid-β 1–42 (Aβ1–42), Tau, and pTau181 concentrations measured from low-retention tubes. a CSF Aβ1–42 concentrations in 0.5-ml aliquots were higher than 0.1-ml aliquots when measured with the AlzBio3 assay. b and c Aliquot size did not have an appreciable impact on Tau and pTau181 concentrations. d CSF Aβ1–42 concentrations were biased toward higher concentrations in 0.5-ml aliquots (rs = 0.84, p = 0.002). e CSF Tau concentrations were similar between 0.1-ml and 0.5-ml aliquots (rs = 0.99, p < 0.0001). f CSF pTau181 concentrations were similar between 0.1-ml and 0.5-ml aliquots (rs = 0.97, p < 0.0001). Young normal control subjects = black, triangles, n = 20; subjects with Alzheimer’s disease = red, circles, n = 81; solid line = line of identity (y = x); rs = Spearman’s rank-correlation coefficient