MAPT and Alzheimer disease: Concordance between BBM p-tau 181 and CSF Aβ42/40 ratio was found to be limited (50%) in a memory clinic setting,85 questioning its validity to detect early Aβ pathology.29 However, BBM p-tau 217, as in our study, seems to be a better biomarker of early AD pathology.32,69 Our cost-effectiveness estimates rely on the assumption that AAT is equally effective regardless of the strategy used to identify eligible patients (i.e., BBM-, CSF-, or PET-based approach), which might not be the case due to differences in the temporal evolution of these biomarkers with underlying disease pathology).