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Updated: Jan 7, 2026
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Dried Blood Spot Collection of Health Biomarkers to Maximize Participation in Population Studies
Published on: January 28, 2014
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Biomarkers
Rianne N Esquivel1, Shriya Mathur1, Christine Parker2
1GSK, Collegeville, PA, USA.
Alzheimer'S & Dementia : the Journal of the Alzheimer'S Association
|December 26, 2025
Summary
Blood biomarkers like PrecivityAD and pTau181 can accelerate Alzheimer's disease clinical trials by prescreening for amyloid positivity. This reduces patient burden and operational costs associated with traditional confirmatory testing.
Area of Science:
- Neurology
- Biomarkers
- Clinical Trials
Background:
- Clinical trials for early Alzheimer's disease (AD) face slow enrollment due to low amyloid positivity rates.
- Confirmatory testing (CSF biomarkers, amyloid PET) increases patient burden and operational challenges.
- Blood-based biomarkers offer a potential solution for prescreening and enriching trial populations.
Purpose of the Study:
- To evaluate the efficacy of blood-based biomarkers (PrecivityAD and Elecsys pTau181) in prescreening for amyloid positivity in early AD clinical trials.
- To assess the impact of these biomarkers on reducing the need for invasive confirmatory testing.
Main Methods:
- Incorporated PrecivityAD and Elecsys pTau181 assays into the screening process for the PROGRESS-AD phase 2 trial.
- Compared blood biomarker results with amyloid PET and CSF (Aβ42/40 ratio) for ROC analysis.
- Analyzed positive percent agreement (PPA), negative percent agreement (NPA), and positive predictive value (PPV) against confirmatory tests.
Main Results:
- pTau181 showed PPA of 85.0% and NPA of 59.5%.
- PrecivityAD demonstrated PPA of 64.6% and NPA of 42.9%.
- PrecivityAD had a PPV of 96.4%, and pTau181 had a PPV of 90.0%, significantly reducing screen failure rates to 9.9%.
Conclusions:
- Blood-based biomarkers significantly reduce the need for CSF or PET testing in early AD trials.
- These biomarkers can decrease participant burden, improve trial accessibility, and enhance clinical trial design.
- Further research is needed to address limitations such as incomplete confirmatory results for amyloid-negative individuals and potential biases.
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