Abstract / Summary
INTRODUCTION: We report the development and validation of a novel computational tool to cross-convert plasma pTau217 results from different assays to facilitate recruitment for therapeutic trials and observational studies. METHODS: Participants underwent A{beta} PET imaging and plasma pTau217 measurement on up to three assay platforms across three cohorts. We then developed conversion equations using Deming regression -- collectively named Biomarker Convert -- and evaluated robustness using independent research cohorts. Finally, we modeled the potential impact of pTau217 screening on trial enrollment. RESULTS: While absolute plasma pTau217 concentrations differed, the assays had similar predictive characteristics for A{beta} positivity (LC-MS/MS [C2N], AUC=0.952; Janssen Simoa, AUC=0.946; Lumipulse, AUC=0.929). Biomarker Convert enabled transformation of plasma pTau217 data across assays independent of A{beta} PET and clinical status. Plasma pTau217 reduced A{beta} PET scans in the model screening paradigm by >60%. DISCUSSION: Biomarker Convert equations enable harmonization of plasma pTau217 values from immunoassay and mass spectrometry platforms, supporting direct data comparison.