Benedet AL, Milà-Alomà M, Vrillon A, et al. - The levels of plasma glial fibrillary acidic protein (GFAP, a marker of reactive astrogliosis) were examined throughout the Alzheimer disease (AD) continuum, and were compared with the levels of cerebrospinal fluid (CSF) GFAP.

• In this cross-sectional study, patients in the preclinical and symptomatic stages of AD had increased plasma GFAP levels, with levels higher than those of CSF GFAP.

• Relative to CSF GFAP, plasma GFAP allowed better discrimination between amyloid-β (Aβ)–positive and Aβ-negative individuals, also at the preclinical stage.

• Overall, plasma GFAP is identified to be a sensitive biomarker that performed significantly better than CSF GFAP in indicating Aβ pathology in the early stages of AD.