Clinical Validation of the PrecivityAD2 Blood Test: A Mass Spectrometry-based Test with Algorithm Combining %p-tau217 and Aβ42/40 Ratio to Identify Presence of Brain Amyloid

Overview

Journal Alzheimers Dement

Specialties Neurology
Psychiatry

Date 2024 Mar 16

PMID 38491912

Authors

Matthew R Meyer

Kristopher M Kirmess

Stephanie Eastwood

Traci L Wente-Roth

Faith Irvin

Mary S Holubasch

Venky Venkatesh

Ilana Fogelman

Mark Monane

Lucy Hanna

Gil D Rabinovici

Barry A Siegel

Rachel A Whitmer

Charles Apgar

Randall J Bateman

David M Holtzman

Michael Irizarry

David Verbel

Pallavi Sachdev

Satoshi Ito

John Contois

Kevin E Yarasheski

Joel B Braunstein

Philip B Verghese

Tim West

Affiliations

Soon will be listed here.

Abstract

Background: With the availability of disease-modifying therapies for Alzheimer's disease (AD), it is important for clinicians to have tests to aid in AD diagnosis, especially when the presence of amyloid pathology is a criterion for receiving treatment.

Methods: High-throughput, mass spectrometry-based assays were used to measure %p-tau217 and amyloid beta (Aβ)42/40 ratio in blood samples from 583 individuals with suspected AD (53% positron emission tomography [PET] positive by Centiloid > 25). An algorithm (PrecivityAD2 test) was developed using these plasma biomarkers to identify brain amyloidosis by PET.

Results: The area under the receiver operating characteristic curve (AUC-ROC) for %p-tau217 (0.94) was statistically significantly higher than that for p-tau217 concentration (0.91). The AUC-ROC for the PrecivityAD2 test output, the Amyloid Probability Score 2, was 0.94, yielding 88% agreement with amyloid PET. Diagnostic performance of the APS2 was similar by ethnicity, sex, age, and apoE4 status.

Discussion: The PrecivityAD2 blood test showed strong clinical validity, with excellent agreement with brain amyloidosis by PET.

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