GFAP and Alzheimer disease: In this paper, we evaluated a panel of four novel ultrasensitive electrochemiluminescence (ECL) immunoassays from Meso Scale Diagnostics (MSD; Rockville, MD) of interest in AD: pTau181, total Tau (tTau), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP).