The aim of this study was to systematically evaluate the pre-analytical stability of pTau 217 in K2EDTA plasma, measured using the Lumipulse® G pTau 217 Plasma assay (Fujirebio Europe N.V.). Analyte stability was assessed under commonly encountered handling and storage conditions, including room temperature, refrigerated and frozen storage, repeated freeze/thaw cycles, and comparisons of fresh versus frozen plasma samples in order to support robust specimen management recommendations for clinical research and routine laboratory use.