B-063 Analytical performance of the new assay for pTau217 using LUMIPULSE® system

Background pTau217 has been shown to be a reliable biomarker for detecting amyloid (Aß) pathology associated with Alzheimer’s disease (AD). Fujirebio has developed a Lumipulse pTau217 prototype assay for the LUMIPULSE L2400 to complement the existing commercially available Lumipulse G pTau217 Plasma assay, enabling high-throughput testing. This study presents the analytical performance of the new assay for pTau217. Methods The reagent was developed and validated on a fully automated immunoassay system, LUMIPULSE L2400. Sixty-microliter specimens were assayed using a two-step sandwich immunoassay. The limits of detection (LoD), quantification (LoQ), within-laboratory precision, linearity, interference, and reactivity with endogenous substances were determined. Moreover, the correlation between the new assay and the existing assay was investigated. Data were analyzed using R or Microsoft Excel statistical tool Analyse-it. Results The LoD and the LoQ were 0.008 pg/mL and 0.018 pg/mL, respectively. The within-laboratory precision showed CV 2.8-3.4 %. Linearity was demonstrated over the range 0.026-11.256 pg/mL. No interference was observed with unconjugated (=19.7 mg/dL) or conjugated bilirubin (=20.1 mg/dL), chyle (=1480 FTU), RF (rheumatoid factor, =500 IU/mL), and HAMA (human anti-mouse antibody, =1068.3 ng/mL). The correlation between the kits showed strong correlation with a slope of 0.97 and intercept of 0.010 and a correlation-r of 0.995. Conclusion This preliminary performance evaluation of the new pTau217 assay indicated promising results in terms of low variability, and high sensitivity. These data demonstrate that the new assay system will be useful in enhancing the detection of amyloid pathology. Moreover, with the availability of anti-amyloid therapies, the demand for measuring pTau217 in blood has increased, making our new pTau217 assay a valuable tool for screening suitable patients and monitoring effect of the therapeutic drug.