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Publication
medRxiv

Head-to-head comparison of plasma p-tau217 immunoassays for incipient Alzheimer’s disease in community cohorts

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  • October 9, 2025
  • Thomas Karikari, et al., University of Pittsburgh
Topic/Product:
CNS Disease Panel 120, Neurology
Disease Area:
Alzheimer's Disease
Sample Type:
Plasma

Abstract

Background Plasma p-tau217 is a promising biomarker for detecting incipient AD pathology, but direct comparison of different p-tau217 assays in community-based cohorts are limited.

Methods We evaluated two cohorts from southwestern Pennsylvania, USA; the MYHAT-NI sub-study, which included two-year longitudinal follow-up neuroimaging assessments of Aβ, tau, and cortical thickness; and the Human Connectome Project/CoBRA, targeting a 50:50 split of self-identified Black and non-Hispanic White individuals. Plasma p-tau217 was measured using four different assays: Lumipulse, Johnson&Johnson, ALZpath, and NULISA. Aβ and tau pathologies were assessed with [11C]PiB PET and [18F]Flortaucipir PET, respectively. Clinical Dementia Rating (CDR) and Montreal Cognitive Assessment were used to assess cognitive performance.

Results We included 344 participants (MYHAT-NI: n=111, median age 76 [IQR: 72-80], 54% female; HCP/CoBRA: n=234, median age 62 [IQR: 52-70], 65% female). All four p-tau217 assays exhibited moderate to strong cross-platform correlations (Spearman correlations of 0.40 – 0.86), and statistically equivalent AUCs (of 0.84-0.90) for determining Aβ positivity.

Conclusions Our findings showed strong equivalent performances of plasma p-tau217 assays to identify amyloid positivity across two highly diverse cohorts of community-dwelling older adults.

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Authors & Affiliations

Rebecca A. Deek13, Wasiu G. Balogun234, Xuemei Zeng234, Gallen Triana-Baltzer5, Tharick A. Pascoal236, Hartmuth C. Kolb5, Beth Snitz36, Ann D. Cohen23 and Thomas K. Karikari234*

1. Department of Biostatistics and Health Data Science, School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
2. Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
3. Alzheimer’s Disease Research Center, University of Pittsburgh, Pittsburgh, PA, USA
4. Biofluid Biomarker Laboratory, Western Psychiatric Hospital, University of Pittsburgh Medical Center, Pittsburgh PA, USA
5. Johnson & Johnson, La Jolla, California, USA
6. Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA

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Steve Williams, MD, PhD

CSO

Dr. Willams serves as the company’s Chief Scientific Officer. He was previously Chief Medical Officer at Standard Biotools and at SomaLogic where he pioneered the discipline for discovery and validation of predictive, diagnostic and prognostic models using machine-learning applied to large-plex proteomics. 20 such tests were used for drug characterization, safety and efficacy when incorporated in clinical drug trials at Pharma/Biotech and 17 different multivariate tests were validated and translated into regulated healthcare uses. Prior to SomaLogic, Dr. Williams was at Pfizer in the UK and the USA as a clinical triallist in Translational Medicine, and subsequently as VP, Global Clinical Technology. He sat on the National Advisory Council for the National Institute of Biomedical Imaging and Bioengineering, the Executive Committee for the FNIH Biomarkers Consortium, and worked with FDA and PhRMA on developing evidentiary standards for biomarker qualification. Dr. William’s medical training was in London, at Charing Cross and Westminster Medical School, followed by a PhD in medicine/physiology at the same institution and training in Radiology at the University of Newcastle Upon Tyne. Steve is co-inventor on 26 proteomics patents and author/coauthor on multiple foundational proteomics manuscripts.

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Justin McAnear

CFO

Mr. McAnear serves as the company’s Chief Financial Officer. He brings over 25 years of operational and financial leadership experience across various sectors and was instrumental in taking 10x Genomics public in 2019, serving as its CFO for over five years. Mr. McAnear served for over 3 years as Tesla’s VP of Worldwide Finance and Operations, supporting landmark initiatives such as the Model X and Model 3 launches and Solar City acquisition.  He also held various roles at Apple and J&J earlier in his career and served as a naval officer and aviator for over 9 years.