Application of the Bead-Based Technique in Neurodegeneration: A Literature Review.

BACKGROUND: Alzheimer's disease (AD) is the most common disease causing neurodegeneration. The lower concentration of ß-amyloid 1-42 (Aß1-42) together with increased levels of total tau protein (T-tau) and phosphorylated tau protein (P-tau) in the cerebrospinal fluid (CSF) make a panel of well-established biomarkers in AD diagnosis. Addition of novel biomarkers to the gold standard biomarker panel might improve the diagnostic accuracy of neurodegeneration. This goal might be reached by the use of multiplexing, which is a simultaneous measurement of multiple analytes in a single sample volume and within a single cycle or run. OBJECTIVE/METHODS: Therefore the aim of the current review was to present, according to our best knowledge, available data concerning the evaluation of concentrations and diagnostic accuracy of well-established biomarkers in AD as well as novel biomarkers analyzed with the use of the bead-based technique. Additionally we discuss the utilization of the bead-based technique as compared to the conventional ELISA method. RESULTS: Literature data indicate that the bead-based technique revealed diagnostic sensitivity, specificity and coefficients of variation at the levels similar to ELISA. Moreover, an addition of novel biomarkers (tested by means of the bead-based technique) to the gold standard biomarker panel improved the diagnostic accuracy of neurodegeneration. CONCLUSION: Review of literature data shows that the combined analysis of classical CSF biomarkers with novel biomarkers might increase the specificity and sensitivity of performed tests. However, we concluded that the replacement of conventional ELISA with the bead-based technique requires new reference intervals for Aß1-42, T-tau and P-tau concentrations.