Work

Stability of plasma pTau217/Aβ42 ratio with delayed blood processing

Year: 2026

Type: article

Abstract: INTRODUCTION: Blood-based biomarkers may improve access to Alzheimer's disease diagnosis, but use may be limited in clinics without on-site processing capability. We evaluated the stability of the plasma phosphorylated tau 217 (pTau217)/amyloid beta 42 (Aβ42) ratio after delayed whole-blood processing. METHODS: We compared blood processed within 2 h or held at 4°C for approximately 24 or 48 h before centrifugation and analysis using the Fujirebio Lumipulse G1200. Stability was assessed using ordinary least squares regression, error index, Bland-Altman analysis, and Deming regression. RESULTS: = 0.998). Both delayed conditions met prespecified regression and error-index criteria. Mean absolute percent error was 5.6% at 24 h and 9.8% at 48 h. Deming regression showed no constant bias, although proportional bias was observed at 48 h. No bias was observed for individual analytes for up to 48 h. DISCUSSION: The pTau217/Aβ42 ratio in refrigerated whole blood remained stable for 24 h, with possible utility up to 48 h, supporting more flexible specimen-transport workflows.

Source: Alzheimer s & Dementia Diagnosis Assessment & Disease Monitoring

DOI: 10.1002/dad2.70517