Concordance of CSF measures of Alzheimer's pathology with amyloid PET status in a preclinical cohort: A comparison of Lumipulse and established immunoassays

Introduction We assessed the concordance of cerebrospinal fluid (CSF) amyloid beta (Aβ) and tau measured on the fully automated Lumipulse platform with pre‐symptomatic Alzheimer's disease (AD) pathology on amyloid positron emission tomography (PET). Methods In 72 individuals from the Insight 46 study, CSF Aβ40, Aβ42, total tau (t‐tau), and phosphorylated tau at site 181 (p‐tau181) were measured using Lumipulse, INNOTEST, and Meso Scale Discovery (MSD) assays, and inter‐platform Pearson correlations were derived. Logistic regressions and receiver‐operating characteristic analysis generated CSF cut‐points optimizing concordance with 18F‐florbetapir amyloid PET status (n = 63). Results Measurements of CSF Aβ, p‐tau181, and their ratios correlated well across platforms (r 0.84‐.94, P