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Dual Blood Markers Sharpen Alzheimer’s Diagnosis by Cutting False Positives

A later-stage tau signal helps doctors tell symptomatic Alzheimer’s from early brain changes.

Overview

  • A peer-reviewed study in The Lancet Neurology reports that adding eMTBR-tau243 to p-tau217 identified clinically established Alzheimer’s with about 80% accuracy and lowered false positives to 16%.
  • Researchers tested 572 symptomatic patients in the BioFinder2 cohort and found p-tau217 was highly sensitive to brain amyloid, with 97% of high p-tau217 cases also showing amyloid on brain measures.
  • People who were positive for both blood markers declined faster on cognitive tests and showed rising tau in the brain over time, indicating stronger prognostic value.
  • The new eMTBR-tau243 assay currently relies on mass spectrometry, so teams are working to simplify the test and validate it across larger and more diverse groups before routine use in primary care.
  • p-tau217 alone can turn positive years before symptoms, which boosts early detection but can blur diagnosis in symptomatic patients, so the later-stage tau signal improves staging and reduces misdiagnosis.