Brain health
p-tau217
A phosphorylated tau biomarker associated with Alzheimer disease pathology.
What it measures
Tau phosphorylated at threonine 217 measured in blood or CSF.
Why it matters
Strongly associated with Alzheimer-type amyloid/tau pathology in validated clinical contexts.
How to interpret it
Interpret using validated assays and disease-specific pathways, not as a general cognitive-aging screen.
Important limitations
Clinical implementation, thresholds and intended-use populations are assay-specific.
Evidence status
Emerging biomarker
High-value emerging Alzheimer disease biomarker; not a general biomarker of aging.
Research & guidance
Original papers, validation studies, reviews and clinical guidance connected to this measurement.
systematic review
Blood biomarkers for diagnosis and differential diagnosis of Alzheimer's disease in real-world clinical populations: A systematic review
Alzheimer's & Dementia · 2026
Across real-world clinical studies, plasma p-tau217 showed consistently high diagnostic performance; assay and population heterogeneity remain important.
systematic review / meta-analysis
Blood phosphorylated Tau217 distinguishes amyloid-positive from amyloid-negative subjects in the Alzheimer's disease continuum. A systematic review and meta-analysis
Journal of Neurology · 2025
Supports plasma p-tau217 as a strong marker of amyloid-positive Alzheimer disease biology in studied clinical populations.
prospective cohort
Blood-based biomarkers of Alzheimer's disease and incident dementia in the community
Nature Medicine · 2025
Community cohort evidence links p-tau217 and other plasma markers with incident dementia, while positive predictive value remains limited in general populations.
For education and evidence exploration, not diagnosis or individualized medical advice.