Fig. 1: Plasma tau species levels across clinical groups in cohort 2.

Box plots of the z-scores in plasma p-tau181, tau212–221, p-tau217, tau195–209, p-tau199, p-tau202, p-tau205 and p-tau231 levels quantified by our MS method (n = 51). Participants were classified according to cognitive status: CU and CI and amyloid PET uptake positivity (centiloid > 24). To facilitate comparison among peptides, z-scores are provided; for absolute concentrations, see Supplementary Fig.3. CU− was used as the reference group. The box plots depict the median (horizontal bar) and 25th to 75th percentiles (hinges), and whiskers indicate 10th and 90th percentiles. Statistical analysis across groups was performed using ANOVA (two-sided), and Tukey contrasts were used to account for multiple comparisons (*P < 0.05, **P < 0.01, ***P < 0.001). Exact significant P values: p-tau181 P_{CU− vs CI+} = 0.0352; p-tau205 P_{CU− vs CI+} < 0.001; p-tau217 P_{CU− vs CI+} < 0.001, P_{CU+ vs CI+} = 0.0148, P_{CI+ vs CI−} = 0.0026; and p-tau231 P_{CU− vs CI+} = 0.0015.