Amyloid ratios in plasma and CSF are biomarkers of pre‐symptomatic Alzheimer’s disease

While not as robust as CSF ratios, plasma Aβ₄₂/Aβ₄₀ and Aβ₄₂/tau ratios can isolate cognitively healthy participants with lower risk from participants with a higher risk of cognitive decline. Thus, plasma represents a less invasive medium for the biomarker classification of aging participants.