Plasma p-tau217 in Alzheimer disease: Lumipulse and ALZpath SIMOA head-to-head comparison

Background: Plasma phosphorylated ptau217 (ptau217) has been shown to be one of the most accurate diagnostic markers for Alzheimer disease (AD). No studies have compared the clinical performance of p tau217 as assessed by the fully automated Lumipulse and SIMOA ALZpath ptau217. Aim: To evaluate the diagnostic accuracy of Lumipulse and SIMOA plasma ptau217 assays for AD. Methods: The study included 392 participants, 162 with AD, 70 with other neurodegenerative diseases (NDD) with CSF biomarkers and 160 healthy controls. Plasma ptau217 levels were measured using the Lumipulse and ALZpath SIMOA assays. The ability of ptau217 assessed by both techniques to discriminate AD from NDD and controls was investigated using ROC analyses. Results: Both techniques showed high internal consistency of ptau217 with similar correlation with CSF ptau181 levels. In head to head comparison, Lumipulse and SIMOA showed similar diagnostic accuracy for differentiating AD from NDD (area under the curve 0.952, 95%CI 0.927 0.978 vs 0.955, 95%CI 0.928 0.982, respectively) and HC (AUC 0.938, 95%CI 0.910 0.966 and 0.937, 95% CI0.907 0.967 for both assays). Conclusions: This study demonstrated the high precision and diagnostic accuracy of ptau217 for the clinical diagnosis of Alzheimer disease using either fully automated or semi-automated techniques. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The research is supported by Airalzh Foundation AGYR2021 Life-Bio Grant, the Italian Ministry of University and Research PRIN COCOON (2017MYJ5TH) and PRIN 2021 RePlast (20202THZAW), the Italian Ministry of Health, Grant/Award Number: RF-2018-12366209 and PNRR-Health PNRR-MAD-2022-12376110. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics Comittee of ASST SPedali CIvili of Brescia gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors