MIFlowCyt‐EV: a framework for standardized reporting of extracellular vesicle flow cytometry experiments

TLDR

Extracellular vesicles are small, heterogeneous particles that are difficult to measure, and flow cytometry—though a key technology—has produced controversial results due to instrument limitations, lack of robust methods, ambiguous data interpretation, and a field‑wide absence of a standardized reporting framework. To remedy these problems, a working group of EV‑flow cytometry researchers created a consensus framework outlining the minimum information required for reporting such experiments. The resulting MIFlowCyt‑EV framework integrates the MISEV and MIFlowCyt standards, providing a structure for documenting sample staining, EV detection, measurement, and experimental design while remaining flexible to future instrument and method advances. By ensuring consistent reporting, MIFlowCyt‑EV is expected to enable quantitative comparison across laboratories and facilitate the development of improved instruments and assays for extracellular vesicle measurement.

Abstract

ABSTRACT Extracellular vesicles (EVs) are small, heterogeneous and difficult to measure. Flow cytometry (FC) is a key technology for the measurement of individual particles, but its application to the analysis of EVs and other submicron particles has presented many challenges and has produced a number of controversial results, in part due to limitations of instrument detection, lack of robust methods and ambiguities in how data should be interpreted. These complications are exacerbated by the field's lack of a robust reporting framework, and many EV‐FC manuscripts include incomplete descriptions of methods and results, contain artefacts stemming from an insufficient instrument sensitivity and inappropriate experimental design and lack appropriate calibration and standardization. To address these issues, a working group (WG) of EV‐FC researchers from ISEV, ISAC and ISTH, worked together as an EV‐FC WG and developed a consensus framework for the minimum information that should be provided regarding EV‐FC. This framework incorporates the existing Minimum Information for Studies of EVs (MISEV) guidelines and Minimum Information about a FC experiment (MIFlowCyt) standard in an EV‐FC‐specific reporting framework (MIFlowCyt‐EV) that supports reporting of critical information related to sample staining, EV detection and measurement and experimental design in manuscripts that report EV‐FC data. MIFlowCyt‐EV provides a structure for sharing EV‐FC results, but it does not prescribe specific protocols, as there will continue to be rapid evolution of instruments and methods for the foreseeable future. MIFlowCyt‐EV accommodates this evolution, while providing information needed to evaluate and compare different approaches. Because MIFlowCyt‐EV will ensure consistency in the manner of reporting of EV‐FC studies, over time we expect that adoption of MIFlowCyt‐EV as a standard for reporting EV‐ FC studies will improve the ability to quantitatively compare results from different laboratories and to support the development of new instruments and assays for improved measurement of EVs.