Emerging Biomarkers and New Diagnostic Technologies in Alzheimer's Disease

Abstract

Introduction: Alzheimer’s disease (AD) is one of the major global public health challenges, especially due to its progressive nature and the growing impact on patients, families, and healthcare systems. In this context, developing new, more accessible, and less invasive biomarkers is essential to enable early detection and clinical monitoring of AD, particularly in populations with limited access to healthcare services. Objective: To investigate the main biomarkers used in the early diagnosis and clinical monitoring of Alzheimer’s disease, with emphasis on recent technological advances. Methods: This is an integrative literature review conducted in the PubMed, BVS, and SciELO databases, with a search carried out between October 10 and 22, 2025. Original studies published between 2015 and 2025 that evaluated plasma or serum biomarkers in humans for early diagnosis or clinical monitoring of AD were included. Study selection and data extraction were performed independently by two reviewers. Results: The findings indicate that biomarkers such as p-tau217, the Aβ42/Aβ40 ratio, and ADAM10 stand out for their ability to detect amyloid positivity, alterations in tau metabolism, and early cognitive decline. Techniques based on mass spectrometry, molecular fluorescence, and multimodal analytical approaches demonstrated high diagnostic performance, reinforcing their clinical potential. Although salivary biomarkers showed low accuracy, plasma-based studies revealed strong correlations with PET imaging and cognitive indicators. Conclusion: Plasma biomarkers represent strategic tools to expand access to early AD diagnosis, especially within the Brazilian Unified Health System (SUS) and in regions marked by structural inequalities, such as the Amazon, where long distances, scarcity of specialists, and limited diagnostic infrastructure reinforce the need for less invasive, cost-effective, and operationally simple methods. Realizing this potential requires advances in laboratory standardization, validation across diverse population profiles, and continuous investment in research, technological innovation, and professional training.