NEFL and Alzheimer disease: Current revised 2023 Alzheimer’s Association (AA) criteria differentiates between two broad categories of AD fluid biomarkers related to AD pathogenesis: (1) core AD fluid biomarkers (the CSF ratio of amyloid-β [Aβ42/40], phosphorylated tau-181 and plasma 217 [p-tau181, p-tau217]) and (2) non-specific biomarkers involved in other neurodegenerative disorders pathology, including neurofilament light (Nfl) and glial fibrillary acidic protein (GFAP) (AAIC, 2024).