Using Immunomagnetic Reduction to Assay ReagentStability of Biomarkers Associated with Alzheimerâ??sDisease

Plasma biomarker assays have become a trend for risk evaluation in Alzheimer’s disease. Several studies have been performed to explore their preclinical performance. However, there are very few studies on the storage stability of the reagents used in these assays. The determination of the storage stability of reagents is important because reagents may be stored for a few months prior to end use. In this work, the stability of the reagents used for assaying plasma amyloid β 1-40 (Aβ1-40), Aβ1-42 and total tau protein (Tau) was assessed using immunomagnetic reduction. Reagents immediately after synthesis and reagents in opened vials were used to assay the concentrations of Aβ1-40, Aβ1-42 and Tau in human plasma samples. The recovery rates of the concentrations of biomarkers at different times after synthesis of open vial were calculated to determine the period of stability of reagents. The results showed that the reagents stored at 2°C-8°C were stable for at least 52 weeks. The reagents in open vials were stable for at least six weeks. These stabilities indicate that the reagents used to assay plasma Aβ1-40, Aβ1-42 and Tau levels are verifiably qualified for clinical use.