Harmonizing biofluid specimen collection and biomarker quantification in Diverse Vascular Contributions to Cognitive Impairment and Dementia (DVCID) study

INTRODUCTION: Multicenter clinical studies inherently face challenges in maintaining consistency across sites. Here we share the design and implementation of standard operating procedures (SOPs) for the Diverse Vascular Contributions to Cognitive Impairment and Dementia (DVCID) study. METHODS: The Repository Core implements harmonized protocols for biospecimen collection and preparation. Pre-, intra-, and post-analytical factors influencing sample integrity and data reliability are addressed. Stringent measures are applied to obtain reproducible biomarker data. RESULTS: Rigorous post-analytical quality control ensures assay variabilities within acceptable limits. Interim analyses, presented as proof of concept, show differences in selected plasma biomarkers across sex and race/ethnicity after covariate adjustment. These efforts establish a strong foundation for the high-quality data generated in DVCID, supporting reliability of downstream analyses. DISCUSSION: This work demonstrates a standardized framework to enhance data comparability, aiming to inform and facilitate future multicenter biomarker studies. Interim findings also highlight the potential need for ethnoracially tailored cut-offs when interpreting blood-based biomarker data.