Flow cytometry was thrust into the spotlight by the AIDS epidemic in the 1980s as it provides a quick and accurate way to count CD4 + and CD8 + T cells in HIV-infected patients.

B) Fluorescence microscope image shows that CDgB stains B cells but not T cells. C) Flow cytometry graph of CDgB fluorescence vs SSC between T cell and B cell populations.

However, the challenging nature of EVs, instrument limitations and ambiguity around methods and data interpretation means that it requires specialized flow cytometry technology and standards ...