GFAP and Alzheimer disease: One such method, single molecule array (Simoa), enabled the introduction of high sensitivity immunoassays for numerous blood-based biomarkers of relevance in AD research and potentially diagnostics, including Amyloid beta42/40 (Aβ42/40), phosphorylated-tau isoforms, glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) (1).