GFAP and Alzheimer disease: Current revised 2024 Alzheimer’s Association (AA) criteria distinguish three broad categories of AD fluid biomarkers related to AD pathogenesis: (1) core AD fluid biomarkers [the CSF ratio of amyloid-β (Aβ42/40), phosphorylated and secreted AD tau (p-tau 217, p-tau-181, and p-tau 231)], (2) non-specific biomarkers involved in other neurodegenerative pathology, including neurofilament light (NfL) and glial fibrillary acidic protein (GFAP), and (3) biomarkers of non-AD pathology (vascular brain injury, alpha-synuclein [αSyn]) (Jack et al., 2024).