Both exosomes and oncosomes are extracellular vesicles produced by normal and cancerous cells respectively, and are found in most bodily fluids. Oncosomes are of increasing clinical and scientific importance because they are involved in cancer metastasis. A device is presented to meet the challenge of high throughput and high-volume processing of clinical fluids, by continuously separating oncosomes/exosomes from the clinical fluid, and then separating the oncosomes from the exosomes. The device separates based upon physicochemical differences (such as size, density, and charge) of the exosomes/oncosomes rather than upon affinity techniques. Field flow fractionation will show feasibility and discover the physical property differences that exist between oncosome and exosome from cultured cells of melanoma and melanocytes respectively. Serum will be used with several split-flow lateral-transport thin separation (SPLITT) instruments. SPLITT will be used to separate exosome from oncosome and compared against standard techniques for exosome refinement. Upon successful completion of these technical objectives, a detailed cost/time analysis will be used to justify the evaluation of development of beta prototype, additional clinical samples, and cancer types in Phase II funding.