Blood samples were centrifuged immediately after draw and stored at −80°C. Plasma Aβ42/40 was determined by the Quest AD‐Detect, beta–amyloid 42/40 ratio, plasma test (Quest Diagnostics, San Juan Capistrano, CA; test code: 11786), which uses high‐throughput liquid chromatography/tandem mass spectrometry (LC‐MS/MS). MS‐based approaches have yielded improved classification between Aβ PET negative and positive participants compared to immunoassays.
6 (link) An initial clinical validation study of the Quest AD‐Detect plasma test demonstrated high AUC for differentiating Aβ PET positive from PET negative individuals
38 (link) and comparable performance to other validated MS‐based assays.
3 (link),
4 (link),
5 (link),
6 (link) Other plasma biomarkers, including t‐tau (N3PA Advantage Kit, Item #101995), p‐tau181 (pTau‐181 Advantage V2 kit, Item #103714), NfL and GFAP (Neurology 2‐Plex B kit, Item #103520), were analyzed using single‐molecule array immunoassays (Quanterix Corporation, Lexington, MA).
39 (link)
6 (link) An initial clinical validation study of the Quest AD‐Detect plasma test demonstrated high AUC for differentiating Aβ PET positive from PET negative individuals
38 (link) and comparable performance to other validated MS‐based assays.
3 (link),
4 (link),
5 (link),
6 (link) Other plasma biomarkers, including t‐tau (N3PA Advantage Kit, Item #101995), p‐tau181 (pTau‐181 Advantage V2 kit, Item #103714), NfL and GFAP (Neurology 2‐Plex B kit, Item #103520), were analyzed using single‐molecule array immunoassays (Quanterix Corporation, Lexington, MA).
39 (link)
