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

https://doi.org/10.1002/alz.13026

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

Abstract

INTRODUCTION

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

METHODS

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.

RESULTS

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.

DISCUSSION

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.