MISEV2023 and why 'exosome' is often the wrong word

What MISEV2023 actually defines

MISEV2023 is the 2023 update to the Minimal Information for Studies of Extracellular Vesicles, a consensus framework maintained by the International Society for Extracellular Vesicles. It does not regulate anything on its own, but it sets out what a research or production team needs to report before calling a preparation an 'exosome,' a 'microvesicle,' or simply an 'extracellular vesicle' (EV). The guidance exists because particles isolated from biological fluids vary enormously in size, origin, and composition, and loose terminology makes it difficult to compare one product's data against another's.

The framework asks for specifics: the source cell or tissue, the isolation method, particle size distribution, particle concentration, and which protein markers were used to confirm the particles are vesicles rather than debris or protein aggregates. Tetraspanin markers such as CD9 and CD81 are often included in characterization panels, but their presence alone does not establish that a preparation formed through the specific intracellular pathway that defines a true exosome.

Why 'exosome' is often the wrong word

Under MISEV2023, 'exosome' is a narrow term. It refers specifically to vesicles that bud from inside a cell through the endosomal pathway and are then released. MISEV2023 recommends EV terminology unless exosome biogenesis is demonstrated, and reporting source, size, concentration and markers. Absent that evidence, the broader term 'extracellular vesicles' applies, with 'small EV' or 'medium/large EV' as size-based descriptors.

This is not a pedantic distinction. A supplier that labels a product 'exosomes' without biogenesis data is making a claim the underlying data does not support, and ambiguous labeling makes it harder for a buyer to document the product internally. Characterization reports built on nanoparticle tracking analysis (NTA), ELISA, and tetraspanin markers describe particle size, concentration, and surface markers. On their own, they do not establish that the particles are exosomes in the strict MISEV2023 sense.

What this means for procurement and internal documentation

For clinics and distributors, the practical takeaway is to treat 'exosome' as shorthand rather than a verified biological classification unless a supplier can point to specific biogenesis evidence. Internal records, intake forms, and any materials shared with a medical director should reflect what the characterization data actually shows, not just the product name on the label.

When comparing suppliers, ask for the same categories of information MISEV2023 asks researchers to report, so that answers can be compared against each other rather than taken at face value from marketing copy.

• Source cell or tissue used for the preparation
• Isolation method (for example, ultracentrifugation, tangential flow filtration, or size-exclusion chromatography)
• Particle size distribution and concentration data (NTA or equivalent)
• Marker panel used (ELISA, SP-IRIS) and which tetraspanins were tested
• Any biogenesis evidence supporting an 'exosome' versus a general 'EV' classification

Regulatory context: terminology does not change the framework

Terminology aside, FDA states there are no FDA-approved exosome products. Such products are generally regulated as biologic drugs under section 351 of the Public Health Service Act, rather than under the section 361 framework that applies to some minimally manipulated tissue products. That regulatory posture exists independent of what a given preparation is called.

Purchase and clinical-use decisions belong to the licensed physician with their own regulatory counsel. These products are not FDA approved or licensed for any disease or condition. Information is for licensed healthcare professionals and is not medical or legal advice.