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Cognition & social

CSF biomarkers (Aβ42, p-tau)

DELiquor-Biomarker (Aβ42, p-Tau)

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Cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease are proteins measured in lumbar puncture samples that reflect core brain pathologies: Aβ42 (and the Aβ42/40 ratio) decreases in CSF as amyloid is sequestered into plaques, while phospho-tau 181 and 217 (p-tau181, p-tau217) and total tau (t-tau) increase with neurofibrillary tangle pathology and neurodegeneration. Together they operationalise the A/T/N (amyloid/tau/neurodegeneration) biomarker framework endorsed by the 2024 Alzheimer's Association diagnostic criteria, enabling biological rather than purely clinical diagnosis. CSF biomarkers show strong concordance with amyloid and tau PET and can detect Alzheimer's pathology 15–20 years before symptomatic onset; their main limitation is the invasiveness of lumbar puncture. Plasma-based equivalents (especially p-tau217) are rapidly maturing and approaching CSF-level diagnostic accuracy.

Sources

  1. Blennow K, Dubois B, Fagan AM, Lewczuk P, de Leon MJ, Hampel H. (2015). Clinical utility of cerebrospinal fluid biomarkers in the diagnosis of early Alzheimer's disease. *Alzheimer's & Dementia*doi:10.1016/j.jalz.2014.02.004
  2. Hampel H, O'Bryant SE, Molinuevo JL, Zetterberg H, Masters CL, Lista S, Kiddle SJ, Batrla R, Blennow K. (2018). Current state of Alzheimer's fluid biomarkers. *Acta Neuropathologica*doi:10.1007/s00401-018-1932-x