Biofluid Biomarkers of Alzheimer's Disease: Progress, Problems, and Perspectives

Since the establishment of the biomarker-based A-T-N (Amyloid/Tau/Neurodegeneration) framework in Alzheimer's disease (AD), the diagnosis of AD has become more precise, and cerebrospinal fluid tests and positron emission tomography examinations based on this framework have become widely accepted. However, the A-T-N framework does not encompass the whole spectrum of AD pathologies, and problems with invasiveness and high cost limit the application of the above diagnostic methods aimed at the central nervous system. Therefore, we suggest the addition of an X to the A-T-N framework and a focus on peripheral biomarkers in the diagnosis of AD. In this review, we retrospectively describe the recent progress in biomarkers based on the A-T-N-X framework, analyze the problems, and present our perspectives on the diagnosis of AD.

Automated summary

The diagnosis of Alzheimer's disease (AD) has become more precise with the introduction of the biomarker-based A-T-N (Amyloid/Tau/Neurodegeneration) framework. However, this framework does not cover the entire spectrum of AD pathologies and the invasive nature and high costs of the diagnostic methods for the central nervous system pose limitations. Therefore, adding an X to the A-T-N framework and focusing on peripheral biomarkers in the diagnosis of AD is recommended.