GFAP and Alzheimer disease: The addition of genetic risk scores (AD‐PRSnoAPOE and APOE‐RS) to a panel of plasma biomarkers (p‐tau181, Aβ42/40, GFAP, and NfL), also improved discrimination of LBD from MCI+/AD, and LBD PET Aβ+ from LBD PET Aβ−, in terms of both model fit (P = 0.028 and P = 0.029, respectively) and classification accuracy (AUC improved from 74% to 78%, and 76% to 84%, respectively, see Table S4 in supporting information).