Overview of Immunoanalytical Methods for Determination of Alzheimer's Disease Biomarkers' Triplet in Cerebrospinal Fluid and Blood

Abstract

A triplet of Alzheimer's disease biomarkers includes total (t-tau) protein, phosphorylated tau (p-tau) protein, and β-amyloid 42 (Aβ42). The levels of Alzheimer's disease biomarkers in cerebrospinal fluid are closely related to the underlying neuropathological manifestations demonstrated in the brain in Alzheimer's disease patients. The triplet of the biomarkers significantly differentiates cognitively healthy persons from patients with not only developed Alzheimer's disease but also with mild cognitive impairment and provides prognostic information. The increasing interest in defining different types of dementia using neurobiological indicators stimulates the development of various methods for their detection. The article provides an overview of immunochemical methods that can be used to determine the triplet of Alzheimer's disease biomarkers, namely ELISA, fluorescence and electrochemiluminescence immunoassays, and resembles the ultrasensitive single molecule arrays for the analysis of biomarkers in blood. The possibility to determine the biomarkers simultaneously in a multiplex arrangement and the importance of fully automated methods are mentioned. It draws attention to the need to standardize methods intended for clinical purposes.