GFAP and Alzheimer disease: The diagnoses of the MCI participants were based solely on clinical presentation so we next assessed if plasma biomarker levels could differentiate participants with autopsy- or biomarker verified AD from controls with OND or CN adults in a cross-sectional sample (Table 2) to understand if pTau181 and GFAP identified MCI participants with AD as underlying pathology or if their levels predicted disease progression per se.