Autor:innen:
Christine von Arnim, Ulm (Germany)
José Luis Molinuevo, Barcelona (Spain)
Oskar Hansson, Malmö (Sweden)
Richard Batrla, Rotkreuz (Switzerland)
Tobias Bittner, Basel (Switzerland)
Paul S. Aisen, San Diego (United States)
Robert Baldor, Worcester (United States)
Cynthia Carlsson, Madison (United States)
Samuel Grief, Chicago (United States)
Andreas U. Monsch, Basel (Taiwan)
Eric M. Reiman, Phoenix (United States)
Josep Vilaseca, Barcelona (Spain)
Michael Weiner, San Francisco (United States)
Maryline Simon, Rotkreuz (Switzerland)
Vivienne Stutz, Rotkreuz (Switzerland)
Simone Wahl, Penzberg (Germany)
Udo Eichenlaub, Penzberg (Germany)
Norbert Wild, Penzberg (Germany)
Kaj Blennow, Mölndal (Sweden)
INTRODUCTION
Alzheimer’s disease (AD) diagnosis is performed at specialist centers by clinical evaluation, neuropsychological testing, and confirmatory cerebrospinal fluid (CSF) and/or positron emission tomography (PET) analysis of AD biomarkers. CSF/PET is only performed in few patients due to invasiveness, cost and availability. With the anticipated approval of disease-modifying treatments, blood-based biomarker (BBBM) assays shall support management of patients with suspected AD in primary care. The minimally invasive BBBM assays would measure plasma amyloid-β (Aβ) peptides, thus identifying patients with high likelihood of Aβ pathology. Here, we aim to identify desirable characteristics for BBBM assays and approaches for implementation.
METHODS
An advisory board of neurodegenerative disease experts discussed target populations, performance and practicalities of BBBM assay implementation. Preliminary Aβ(1–42)/(1–40) ratio data of Elecsys® BBBM assays in the Swedish BioFINDER cohort (N=843) were shared (Hansson, AAIC 2019): AUC for prediction of Aβ positivity was 0.8; diagnostic accuracy increased with inclusion of APOE genotype and cognitive function. A population-based model was made to estimate trends in specialist center referrals (2017–23) after BBBM assay introduction.
RESULTS
The recommended target population was patients with mild cognitive impairment or subjective cognitive decline in primary care; future routine use in elderly was encouraged. Assay sensitivity of 85% and specificity of 50% were considered suitable. Pre-analytical sample handling appeared feasible in most primary care settings. Modelling predicted that BBBM assays would increase EU specialist center referrals, thereby increasing the proportion of patients correctly identified with Aβ pathology.
CONCLUSION
While additional testing is needed, Elecsys® BBBM assays were considered beneficial to support early diagnosis of patients with cognitive impairment and feasible for use in primary care.