GFAP and Alzheimer disease: Seventy participants (20 with MCI, 35 with AD, and 15 HC) underwent plasma testing for amyloid-beta 40 (Aβ40), amyloid-beta 42 (Aβ42), the Aβ42/Aβ40 ratio, phosphorylated tau 181 (p-tau181), p-tau217, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), along with cognitive assessments using the Mini-Mental State Examination (MMSE).