P-TAU217 AS A BLOOD-BASED BIOMARKER FOR THE EARLY DIAGNOSIS OF ALZHEIMER'S DISEASE: A LITERATURE REVIEW

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder whose pathophysiology involves, among other mechanisms, the accumulation of cerebral β-amyloid, associated with alterations in tau protein, its hyperphosphorylation, and the formation of neurofibrillary tangles, contributing to synaptic dysfunction and neuronal loss. These changes may occur years before the onset of clinical manifestations, reinforcing the need for strategies capable of identifying the disease at early stages. In this context, this article aimed to evaluate the use of phosphorylated tau at threonine 217 (p-tau217) as a blood-based biomarker for the early identification of AD, considering its relationship with neuropathological changes and its potential diagnostic applications. An integrative literature review was conducted using the PubMed and Virtual Health Library (VHL) databases, with the descriptors “Alzheimer Disease” and “p-tau217”, combined using the Boolean operator AND. Observational studies and controlled clinical trials published between 2024 and 2026, available free of charge and with full-text access, were included, resulting in the selection of 26 studies. The findings indicated an association between plasma p-tau217 levels and changes related to β-amyloid deposition and tau pathology, as well as its potential application in identifying preclinical changes, patient stratification, and longitudinal follow-up. It is concluded that p-tau217 has potential to be incorporated into the investigation of AD, although its clinical application still depends on greater laboratory standardization and the definition of cutoff values.