GFAP and dementia: Upon subsetting our Amsterdam Dementia Cohort sample according to our six a priori defined clinically relevant questions (Aβ+ in the total cohort, Aβ+ in the SCD and MCI subset, AD vs. FTD, controls vs. FTD, AD vs. DLB, controls vs. DLB) and applying the LASSO regression with 1000 iterations, we found that plasma P‐tau181, GFAP and (age‐corrected) NfL are the relevant diagnostic biomarkers while Abeta42/40 did not have additional diagnostic value (Table 2).