New blood test for Alzheimer's sidesteps kidney interference
A refined blood biomarker called brain-derived pTau217 outperforms existing tests by filtering out noise from kidney disease, which can skew results. The finding could accelerate Alzheimer's diagnosis in millions of patients with concurrent kidney problems—a common scenario in aging populations—and open new markets for diagnostic companies.
Originaltitel: Head-to-head comparison of brain-derived pTau217 and total pTau217 for brain amyloid and tau pathology classification
Phosphorylated-tau 217 (pTau217) is currently the most promising blood-based biomarker for accurately detecting Alzheimer’s disease (AD) pathology. However, interference from peripheral tau species in the kidneys or peripheral nerves can hinder diagnostic precision. Recently developed brain-derived pTau217 (BD-pTau217) assays emerge as highly specific tools for detecting AD-related pathological changes in the brain. In this study, we conducted a head-to-head comparison of the NULISAqpcr BD-pTau217 assay and Simoa ALZpath total p-Tau217 assay in two independent, amyloid-PET–characterized Chinese cohorts. Our results demonstrate a strong correlation between BD-pTau217 and total pTau217 (ρ = 0.89 to 0.90), with BD-pTau217 showing significantly reduced interference from kidney dysfunction, as evidenced by weaker associations with blood levels of urea (ρ BD-pTau217 = 0.02 to 0.06, ρ Total-pTau217 = 0.06 to 0.12) and creatinine (ρ BD-pTau217 = 0.03 to 0.08, ρ Total-pTau217 = 0.16 to 0.18). Moreover, BD-pTau217 is more strongly associated with amyloid-PET Centiloid values (ρ BD-pTau217 = 0.78 to 0.80, ρ Total-pTau217 = 0.74 to 0.77) and exhibits superior classification performance for amyloid-β (Aβ) pathology (area under the curve [AUC] BD-pTau217 = 0.96 to 0.98, AUC Total-pTau217 = 0.94 to 0.97). Furthermore, BD-pTau217 outperforms total pTau217 for identifying tau-positive individuals within the Aβ-positive group (AUC BD-pTau217 = 0.89, AUC Total-pTau217 = 0.78), facilitating more accurate disease staging. These findings underscore BD-pTau217 as a highly sensitive and specific blood-based biomarker for AD that has significant potential for early detection, precise classification, and staging of AD-related brain pathology in clinical practice.