Publications & Posters

Equivalence of plasma p-tau217 with cerebrospinal fluid in the diagnosis of Alzheimer’s disease

Alzheimer’s & Dementia | April 20, 2023

Therriault J, Servaes S, Tissot C, Rahmouni N, Ashton NJ, Benedet AL, Karikari TK, Macedo AC, Lussier FZ, Stevenson J, Wang YT, Fernandez-Arias J, Stevenson A, Socualaya KQ, Haeger A, Nazneen T, Aumont É, Hosseini A, Rej S, Vitali P, Triana-Baltzer G, Kolb HC, Soucy JP, Pascoal TA, Gauthier S, Zetterberg H, Blennow K, Rosa-Neto P.

Alzheimers Dement. 2023

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



Plasma biomarkers are promising tools for Alzheimer’s disease (AD) diagnosis, but comparisons with more established biomarkers are needed.


We assessed the diagnostic performance of p-tau181, p-tau217, and p-tau231 in plasma and CSF in 174 individuals evaluated by dementia specialists and assessed with amyloid-PET and tau-PET. Receiver operating characteristic (ROC) analyses assessed the performance of plasma and CSF biomarkers to identify amyloid-PET and tau-PET positivity.


Plasma p-tau biomarkers had lower dynamic ranges and effect sizes compared to CSF p-tau. Plasma p-tau181 (AUC = 76%) and p-tau231 (AUC = 82%) assessments performed inferior to CSF p-tau181 (AUC = 87%) and p-tau231 (AUC = 95%) for amyloid-PET positivity. However, plasma p-tau217 (AUC = 91%) had diagnostic performance indistinguishable from CSF (AUC = 94%) for amyloid-PET positivity.


Plasma and CSF p-tau217 had equivalent diagnostic performance for biomarker-defined AD. Our results suggest that plasma p-tau217 may help reduce the need for invasive lumbar punctures without compromising accuracy in the identification of AD.