This study explored the ability of plasma amyloid beta (Aβ)42/Aβ40 to identify brain amyloid deposition in cognitively unimpaired (CU) individuals.
Plasma Aβ was quantified with an antibody‐free high‐performance liquid chromatography tandem mass spectrometry method from Araclon Biotech (ABtest‐MS) in a subset of 731 CU individuals from the screening visit of the Anti‐Amyloid Treatment in Asymptomatic Alzheimer's (A4) Study, to assess associations of Aβ42/Aβ40 with Aβ positron emission tomography (PET).
A model including Aβ42/Aβ40, age, apolipoprotein E ε4, and recruitment site identified Aβ PET status with an area under the curve of 0.88 and an overall accuracy of 81%. A plasma‐based pre‐screening step could save up to 42% of the total number of Aβ PET scans.
ABtest‐MS accurately identified brain amyloid deposition in a population of CU individuals, supporting its implementation in AD secondary prevention trials to reduce recruitment time and costs. Although a certain degree of heterogeneity is inherent to large and multicentric trials, ABtest‐MS could be more robust to pre‐analytical bias compared to other immunoprecipitation mass spectrometry methods.
Plasma amyloid beta (Aβ)42/Aβ40 accurately identified brain Aβ deposition in cognitively unimpaired individuals from the Anti‐Amyloid Treatment in Asymptomatic Alzheimer's (A4) Study.
The inclusion of the recruitment site in the predictive models has a non‐negligible effect.
A plasma biomarker‐based model could reduce recruitment costs in Alzheimer's disease secondary prevention trials.
Antibody‐free liquid chromatography mass spectrometry methods may be more robust to pre‐analytical variability than other platforms.