Fig. 1

P-tau217 Exhibits Excellent Performance for the Detection of Aβ Pathology in Individuals with MCI/Dementia. Plasma p-tau217 was measured in 108 individuals undergoing diagnostic lumbar puncture for the detection of Alzheimer Disease pathology. Paired plasma samples were analysed for p-tau217. A (i) P-tau217 was nearly four-fold higher in Aβ + vs Aβ- individuals (Mann–Whitney U = 230; p < 0.001). The red dotted line indicates the Youden optimised cut-off. (A) (ii) p-tau217 exhibited excellent performance in the detection of Aβ + status (Area-Under the Curve [AUC]: 0.91; 0.86–0.97). B (i) P-tau217 was significantly elevated in T + vs T- individuals. (ii) Performance of p-tau217 for detection of T + pathology alone gave an AUC of 0.83 (0.75–0.90) which was significantly lower than that for Aβ positivity (DeLong test, p = 0.04). C (i) Significant differences were not seen in concentrations of p-tau217 between A- T- and A- T + individuals or between A + T- and A + T + individuals supporting the role of p-tau217 as a marker of amyloid positivity. (ii)For Aβ + individuals, concentrations were significantly higher (p = 0.03) in individuals with dementia vs MCI due to AD. D (i) CSF p-tau217 was significantly higher in individuals with Aβ positivity. (ii) CSF p-tau217 had lower performance than plasma p-tau217 with an AUC 0.83 (0.75–0.91) with a trend for statistical significance (p = 0.05). (iii) Significant correlations were observed between CSF and plasma p-tau in individuals with Aβ positivity. ****p < 0.0001, ***p < 0.001, ** < 0.01, *p < 0.05, ns: non-significant; AUC: Area-Under-the-Curve