Methods of isolating membrane vesicles from a biological fluid sample are provided. In some embodiments, the methods comprise providing a biological fluid sample comprising membrane vesicles; filtering the biological fluid sample through a filtration module comprising a filter having an average pore diameter of between about 0.01 um and about 0.15 um; and collecting from the filtration module a retentate comprising the membrane vesicles, thereby isolating the membrane vesicles from the biological fluid sample.