There are several biomarkers indicating if symptomatic disease and cognitive decline are caused by Alzheimer’s disease (AD), however, there is less clarity in the preclinical and mild cognitive impairment (MCI) stages. Nicholas Ashton, PhD, University of Gothenburg, Gothenburg, Sweden & King’s College London, London, UK, explains the findings of an investigation into the cross-sectional and longitudinal association of biomarkers with these various AD phenotypes. Phosphorylated tau (P-Tau), glial fibrillary acidic protein (GFAP), and cerebrospinal fluid (CSF) Aβ42/Aβ40 were tested. P-Tau231 was identified as having the highest accuracy to determine AD pathology at the earliest stages of disease and thus, is recommended as a biomarker for cross-sectional screening. For MCI stage screening, p-Tau217 was found to show the largest changes between Aβ+ and Aβ- cohorts. Looking at the longitudinal trajectories of these markers over six years, p-Tau217 was shown to reflect brain atrophy and cognitive decline, monitoring disease progression in amyloid positive patients with subtle cognitive impairment. This interview took place at the AD/PD™ 2022 Conference in Barcelona, Spain.