The presently disclosed subject matter is directed to methods of aiding diagnosis, prognosis, monitoring and evaluation of a disease or other medical condition in a′ subject by detecting a biomarker in microvesicles isolated from a biological, sample from the subject. Moreover, disclosed subject matter is directed to methods of diagnosis, monitoring a disease by determining the concentration of microvesicles within a biological sample; methods of delivering a nucleic acid or protein to a target all by administering microvesicles that contain said nucleic acid or protein; methods for performing a body fluid transfusion by introducing a microvesicle-free or microvesicle enriched fluid fraction into a patient.