Alzheimer's & dementia : the journal of the Alzheimer's AssociationJan 8, 2025

Using blood p-tau217 to improve Alzheimer's risk and brain tau level predictions in Taiwan

Updated Apr 2, 2026

Abstract

showed a 94% accuracy in predicting amyloid PET results.

A cutoff value for p-tau217 could reduce the need for confirmatory amyloid PET scans by 57.5%.
In cases that are positive for amyloid PET and considering anti-amyloid therapy, p-tau217 levels may predict low/intermediate tau burden more effectively than other biomarkers.
A two-step workflow combining p-tau217 measurement and confirmatory amyloid PET could classify Alzheimer's disease patients with low/intermediate tau burden accurately.

Simplified

INTRODUCTION: We integrated plasma biomarkers from the Taiwan Alzheimer's Disease Neuroimaging Initiative and propose a workflow to identify individuals showing amyloid-positive positron emission tomography (PET) with low/intermediate tau burden based on [18F]Florzolotau PET-based quantification.

METHODS: We assessed 361 participants across the Alzheimer's disease (AD) and non-AD continuum and measured plasma phosphorylated tau (p-tau)217, p-tau181, amyloid beta (Aβ)42/40 ratio, neurofilament light chain, and glial fibrillary acidic protein levels at two medical centers. We evaluated the diagnostic potential of these biomarkers.

RESULTS: Among all plasma biomarkers, had the highest consistency with amyloid PET results (area under the curve = 0.94), and a cutoff value could have reduced the number of confirmatory amyloid PET scans by 57.5%. In amyloid PET-positive cases intending to use anti-amyloid therapy, p-tau217 level, along with clinical parameters, had the highest predictive ability for low/intermediate tau burden.

DISCUSSION: A two-step workflow based on p-tau217 and confirmatory amyloid PET could accurately classify AD patients showing low/intermediate tau burden.

HIGHLIGHTS: The emergence of anti-amyloid therapy increases the need to accurately diagnose Alzheimer's disease (AD). The use of plasma biomarkers, especially phosphorylated tau 217 (p-tau217), can help in the diagnosis of AD. P-tau217 is a better predictor of amyloid positron emission tomography (PET) positivity than other core biomarkers. In amyloid PET-positive individuals, p-tau217 can predict tau burden. We propose a two-step workflow to identify AD cases suitable for treatment.

Key numbers

0.94

for

Performance metric for in identifying amyloid positivity.

57.5%

Reduction in PET scans

Percentage reduction in confirmatory amyloid PET scans using cutoff.

361

Participants assessed

Total number of participants in the study.

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Abstract

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