Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring | February 20, 2021

Simrén J, Ashton NJ, Blennow K and Zetterberg H

Alzheimers Dement (Amst). 2021;13:e12145

DOI: https://doi.org/10.1002/dad2.12145

Abstract

Introduction

This study investigated alternative pre‐analytical handling of blood for neurofilament light (NfL) analysis where resources are limited.

Method

Plasma NfL was measured with single molecule array after alternative blood processing procedures: dried plasma spots (DPS), dried blood spots (DBS), and delayed 48‐hour centrifugation. These were compared to standardized plasma processing (reference standard [RS]). In a discovery cohort (n = 10) and a confirmatory cohort (n = 21), whole blood was obtained from individuals with unknown clinical etiology. In the confirmatory cohort, delayed centrifugation protocol was paired with either 37°C incubation or sample shaking to test the effect of these parameters.

Results

Delayed centrifugation (R² = 0.991) and DPS (discovery cohort, R² = 0.954; confirmatory cohort, DPS: R² = 0.961) methods were strongly associated with the RS. Delayed centrifugation with higher temperatures (R² = 0.995) and shaking (R² = 0.975) did not affect this association. DPS (P < 0.001) returned concentrations considerably lower than the RS.

Discussion

DPS or delayed centrifugation are viable pre‐analytical procedures for the accurate quantification of plasma NfL.