A new LC‐MS/MS assay for the quantification of Aβ40 and Aβ42 in plasma: validation and clinical performance

Early detection of Alzheimer’s disease (AD) represents an unmet clinical need. Cerebrospinal fluid (CSF) biomarkers can potentially fulfil this need, but specimen collection is invasive. Blood‐derived biomarkers are preferable, and several studies have shown an association between the Aβ42/40 ratio and amyloid PET status. However, blood diagnostic tests for AD are challenging due to interlaboratory differences in analytical techniques and preanalytical handling. Here we describe the development and validation of a LC‐MS/MS assay to quantify Aβ40 and Aβ42 from plasma and assess clinical performance.