Preliminary performance of the Lumipulse G pTau 217 Plasma prototype assay on plasma samples

Abstract Background Multiple publications demonstrated that plasma pTau species (e.g., 181, 217, and 231) have the potential to be a good predictor of amyloid status by either PET or cerebrospinal fluid (CSF). Such blood‐based biomarker testing could be used as a simple, accessible, and scalable approach to help support the diagnosis of Alzheimer’s disease (AD), avoiding the complexity of CSF sampling, and the high costs and limited availability of PET imaging. Multiple plasma pTau assays, established on different immunoassay platforms, are currently being evaluated in research settings with variable outcomes in terms of analytical and clinical performance. At Fujirebio, an assay for the measurement of plasma pTau217 was developed on the LUMIPULSE G platform to complement the commercially available plasma pTau181 RUO assay. The aim of this study was to determine the preliminary performance of the Lumipulse G pTau 217 Plasma prototype assay. Method The LUMIPULSE G System is a fully automated chemiluminescent enzyme immunoassay platform processing samples in ready‐to‐use immunoreaction cartridges in about 30 minutes. The assay uses an in‐house developed monoclonal antibody for capturing of pTau217. Analytical assay characteristics such as sensitivity, precision and dilutional linearity were determined. The analytical studies included a series of buffer and K 2 EDTA plasma samples, each tested in several replicates. Preliminary clinical performance was explored on a small set of patient and control samples. Result All analytical parameters tested were within the acceptance criteria. All clinical samples tested had a result above the limit of quantification (LoQ). The LoQ was obtained based on the evaluation of low concentrated plasma pTau217 samples. Imprecision was less than 15% CV on buffer‐based as well as plasma samples. Dilutional linearity on spiked samples was within ±20%. The Lumipulse G pTau 217 Plasma prototype assay outperformed the Lumipulse G pTau 181 Plasma RUO assay in a ROC curve analysis of clinically typed patients and controls. Conclusion This preliminary performance evaluation of the Lumipulse G pTau 217 Plasma prototype assay indicated good results in terms of high sensitivity, low variability, dilutional linearity and clinical capability. More studies on well‐characterised and diverse cohorts are needed to confirm the assay’s clinical performance.