Apoptotic bodies are heaver than microvesicles. To differentiate between these, you could do western blot to detect the cleavage of key apoptotic proteins, e.g., caspase-3 (or other caspases), PARP, which are cleaved during apoptosis. You can detect cleaved forms of caspases and possibly PARP in apoptosic bodies, but not microvesicles.