Which biomarker combination in CSF is currently the best-validated diagnostic indicator of Alzheimer's disease pathology, used in research and pre-dementia clinical staging?
- A Elevated Aβ42 + decreased phospho-tau
- B Elevated total tau + elevated phospho-tau 181 + decreased Aβ42 ✓
- C Elevated 14-3-3 protein + decreased Aβ40
- D Elevated neurofilament light chain alone
Explanation
The ATN (Amyloid-Tau-Neurodegeneration) biomarker framework for Alzheimer's disease uses CSF findings: decreased Aβ42 (increased amyloid deposition trapping Aβ42 from CSF), elevated phospho-tau 181 or 231 (marker of tau hyperphosphorylation/neurofibrillary tangle pathology), and elevated total tau (neuronal degeneration). Together, low CSF Aβ42 + elevated p-tau + elevated t-tau constitutes the characteristic AD biomarker signature with high sensitivity and specificity. CSF 14-3-3 protein is used in Creutzfeldt-Jakob disease diagnosis. Amyloid PET and tau PET are imaging equivalents.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.