Monitoring and reporting the composition of plasma and serum to improve biobanks and comparability of extracellular vesicle research: Communication from the ISTH SSC Subcommittee on Vascular Biology.

Transparent reporting is key to improve reproducibility of scientific research. In 2023, the International Society for Extracellular Vesicles (ISEV) updated the "Minimal information for studies of extracellular vesicles" (MISEV) reporting guidelines, and published new recommendations for blood EV research entitled "MIBlood-EV: Minimal information to enhance the quality and reproducibility of blood extracellular vesicle research". The MIBlood-EV recommendations are part of MISEV2023, and promote reporting not only the protocols used for blood collection and handling, but also the composition of the prepared samples that are used to measure extracellular vesicles (EVs). Plasma and serum are commonly used starting materials for EV research; reporting their composition can help to improve reproducibility, comparison of measurement results, and support evidence-based guideline development. We conducted an online survey amongst ISTH EV researchers. Of the twenty respondents, 95% are familiar with MISEV, but 35% are unaware of the 2023 update, and only 65% apply these guidelines to their reports. With regard to MIBlood-EV, 40% are unaware of this reporting tool, and 20% do not follow its recommendations. This is surprising, because most respondents agree that preanalytical variables of blood EV research are not satisfactorily described (75%), confirm that having a standardized reporting tool is beneficial for blood EV research (90%), and consider MIBlood-EV applicable to other fields of ISTH research (80%). In this SSC communication, we summarize the survey results, as well as the background and goals of MISEV, and how MIBlood-EV can be useful to improve the reproducibility of blood research within the ISTH community.