Exploring the stability of Alzheimer's disease plasma biomarkers stored for extended periods at −20°C: Implications for resource-constrained environments

Plasma samples for Alzheimer's disease biomarker analysis are ideally stored at -80°C, which is challenging in low research resource settings. We assessed the stability of pTau181, Aβ₄₂, Aβ₄₀, NfL, and GFAP in plasma stored at -20°C for 2, 4, 6, and 15 weeks using single molecule array assays. No significant variation was observed in pTau181 and Aβ₄₂/Aβ₄₀ ratio across all timepoints. NfL and GFAP showed greater variability. These findings indicate the stability of these Alzheimer's disease related analytes for up to 15 weeks at -20°C though future studies of other biomarkers and timeframes are recommended.