P-tau/aβ42 and aβ42/40 ratios in csf are equally predictive of amyloid pet status

Michelle R. Campbell, Susan Ashrafzadeh-Kian, Ronald C. Petersen, Michelle M. Mielke, Jeremy A. Syrjanen, Argonde C. van Harten, Val J. Lowe, Clifford R. Jack, Joshua A. Bornhorst, Alicia Algeciras-Schimnich

Research output: Contribution to journalArticlepeer-review


Introduction: Measurement of amyloid beta (Aβ40 and Aβ42) and tau (phosphorylated tau [p-tau] and total tau [t-tau]) in cerebrospinal fluid (CSF) can be utilized to differentiate clinical and preclinical Alzheimer’s disease dementia (AD) from other neurodegenerative processes. Methods: CSF biomarkers were measured in 150 participants from the Mayo Clinic Study of Aging and the Alzheimer’s Disease Research Center. P-tau/Aβ42 (Roche Elecsys, Fujirebio LUMIPULSE) and Aβ42/40 (Fujirebio LUMIPULSE) ratios were compared to one another and to amyloid positron emission tomography (PET) classification. Results: Strong correlation was observed between LUMIPULSE p-tau/Aβ42 and Aβ42/40, as well as Elecsys and LUMIPULSE p-tau/Aβ42 and Aβ42/40 (Spearman’s ρ = –0.827, –0.858, and 0.960, respectively). Concordance between LUMIPULSE p-tau/Aβ42 and Aβ42/40 was 96% and between Elecsys p-tau/Aβ42 and both LUMIPULSE ratios was 97%. All ratios had > 94% overall, positive, and negative percent agreement with amyloid PET classification. Discussion: These data suggest that p-tau/Aβ42 and Aβ42/40 ratios provide similar clinical information in the assessment of amyloid pathology.

Original languageEnglish (US)
Article numbere12190
JournalAlzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring
Issue number1
StatePublished - 2021


  • Alzheimer’s disease dementia
  • Amyloid beta 42/40
  • Amyloid positron emission tomography
  • Cerebrospinal fluid biomarkers
  • Elecsys
  • Immunoassay
  • P-tau/Aβ42

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health


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