Analytical and clinical validation of the Lumipulse G plasma p-tau217 assay for clinical implementation.

INTRODUCTION

Although several plasma tau phosphorylated at threonine 217 (p-tau217) immunoassays are now available, comprehensive analytical validation remains limited. We therefore evaluated the Lumipulse G plasma p-tau217 assay and verified established cutoffs for clinical implementation.

METHODS

This study was conducted in two phases: (1) analytical validation of the Lumipulse G plasma p-tau217 assay, assessing precision, lower limit of quantification (LLoQ), selectivity, stability, and interference; and (2) verification of previously established cutoffs using a two-threshold approach in 37 samples with confirmed cerebrospinal fluid (CSF) Aβ42/Aβ40 status.

RESULTS

The assay demonstrated strong analytical performance, with repeatability and intermediate precision (%CV < 7%) and an LLoQ of 0.12 pg/mL. The p-tau217 was stable across freeze-thaw cycles but less so at 4°C, and hemolysis > 2% introduced variability. Cutoff verification showed 97% reproducibility with excellent agreement (ρ = 0.99, p < 0.0001).

DISCUSSION: The Lumipulse assay showed robust analytical performance and reproducibility, supporting clinical use, though certified reference materials are still needed for standardization.