Longevity & AgingAlzheimer's Association Sets Blood Biomarker Standards for AD Diagnosis
The Alzheimer's Association published its first clinical practice guideline on blood-based biomarkers (BBMs) for diagnosing Alzheimer's disease in specialized care settings. Using GRADE methodology and a systematic review, the panel evaluated plasma phosphorylated-tau (p-tau217, p-tau181, p-tau231, %p-tau217) and amyloid-beta ratio (Aβ42/Aβ40) tests against CSF biomarkers, amyloid PET, and neuropathology. The guideline establishes two key performance thresholds: BBMs achieving ≥90% sensitivity and ≥75% specificity can serve as triage tools, while those achieving ≥90% sensitivity and ≥90% specificity can substitute for PET or CSF testing. The panel warns that many currently available commercial tests do not meet these benchmarks, particularly with a single cutoff value.
