The consistency of cerebrospinal fluid amyloid-β (Aβ)42/40 ratio and Aβ42 has not been assessed in the AT(N) classification system. We analyzed the classification changes of the dichotomized amyloid status (A+/A–) in 363 patients tested for Alzheimer’s disease biomarkers after Aβ42 was superseded by the Aβ42/40 ratio. The consistency of Aβ42 and the Aβ42/40 ratio was very low. Notably, the proportions of “false” A+T–patients were considerable (74–91%) and corresponded mostly to patients not clinically diagnosed with Alzheimer’s disease. Our results suggest that the interchangeability of Aβ42/40 ratio and Aβ42 is limited for classifying patients in clinical setting using the AT(N) scheme.
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Pouclet-CourtemancheH, NguyenTB, SkrobalaE, Boutoleau-BretonnièreC, PasquierF, Bouaziz-AmarE, Bigot-CorbelE, SchraenS, DumurgierJ, PaquetC, LebouvierT (2019) Frontotemporal dementia is the leading cause of “true” A–/T+ profiles defined with Aβ42/40 ratio. Alzheimers Dement (Amst)11, 161–169.
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de WildeA, ReimandJ, TeunissenCE, ZwanM, WindhorstAD, BoellaardR, van der FlierWM, ScheltensP, van BerckelBNM, BouwmanF, OssenkoppeleR (2019) Discordant amyloid-β PET and CSF biomarkers and its clinical consequences. Alzheimers Res Ther11, 78.
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