Publications & Posters

Plasma pTau-217 and N-terminal tau (NTA) enhance sensitivity to identify tau PET positivity in amyloid-β positive individuals

Alzheimer’s & Dementia | November 3, 2023

Woo MS, Tissot C, Lantero-Rodriguez J, Snellman A, Therriault J, Rahmouni N, Macedo AC, Servaes S, Wang YT, Arias JF, Hosseini SA, Chamoun M, Lussier FZ, Benedet AL, Ashton NJ, Karikari TK, Triana-Baltzer G, Kolb HC, Stevenson J, Mayer C, Kobayashi E, Massarweh G, Friese MA, Pascoal TA, Gauthier S, Zetterberg H, Blennow K, Rosa-Neto P.

Alzheimers Dement. 2023

This study was performed using Simoa Homebrew assay(s).



We set out to identify tau PET-positive (A+T+) individuals among amyloid-beta (Aβ) positive participants using plasma biomarkers.


In this cross-sectional study we assessed 234 participants across the AD continuum who were evaluated by amyloid PET with [18F]AZD4694 and tau-PET with [18F]MK6240 and measured plasma levels of total tau, pTau-181, pTau-217, pTau-231, and N-terminal tau (NTA-tau). We evaluated the performances of plasma biomarkers to predict tau positivity in Aβ+ individuals.


Highest associations with tau positivity in Aβ+ individuals were found for plasma pTau-217 (AUC [CI95%] = 0.89 [0.82, 0.96]) and NTA-tau (AUC [CI95%] = 0.88 [0.91, 0.95]). Combining pTau-217 and NTA-tau resulted in the strongest agreement (Cohen’s Kappa = 0.74, CI95% = 0.57/0.90, sensitivity = 92%, specificity = 81%) with PET for classifying tau positivity.


The potential for identifying tau accumulation in later Braak stages will be useful for patient stratification and prognostication in treatment trials and in clinical practice.