Analytical considerations and clinical utility of plasma phosphorylated Tau217.

Blood-based biomarkers are an easily available and practical tool for Alzheimer's disease (AD) screening and diagnosis. Plasma phosphorylated Tau217 (p-tau217) is the front-runner candidate for AD diagnosis due to its strong correlation with core AD pathology determined either by cerebrospinal fluid biomarker (CSF) and positron emission tomography (PET) or postmortem examination. While plasma p-tau217 is firmly associated with AD pathology, it is crucial to evaluate its performance in distinguishing AD from mixed pathologies, as brain autopsies have shown the coexisting of AD pathology with other related types of dementia. Moreover, the measurement of AD biomarkers will be a crucial element in defining eligibility for disease-modifying treatment in clinical practice. Moreover, plasma p-tau217 is a highly efficacious biomarker in the early detection of Aβ pathology, making it a feasible test for AD screening in clinical practice. Several assays, including the ALZpath p-tau217 assay and the Fujirebio plasma p-tau217 assay, have been made commercially available for research use. A few studies analytically and clinically have validated these immunoassays as laboratory diagnostic tests for AD diagnosis and differentiating from non-AD neurodegenerative disorders in clinical practice.