Extracellular vesicles (EVs) represent a promising biomarker in several medical areas. Flow cytometry (FC) is one of the most widely-used methods to characterize EVs, providing quantitative information and determination of EV subtypes. EV evaluation represents a challenge as no standardized methods are available to facilitate assessment across different research centers. This is principally because their size falls below the detection limit of most standard flow cytometers and a thorough optimization process is required to ensure instrument-specific sensitivity. We provide an overview of a standardized method to evaluate large EVs using the Attune™ Nxt Acoustic Focusing Flow Cytometer system (Thermo Fisher Scientific).