Abstract: A blood collection and separation system having multi-chamber collection assembly having a longitudinal axis. The assembly in a preferred embodiment is rotatable about its longitudinal axis and an alternate embodiment is rotatable about an axis parallel to its longitudinal axis. A porous separating body at one axial end of one chamber connects with a second chamber and allows flow of the lighter fraction of the blood from the one chamber to the other chamber during centrifugation, but blocks flow of the heavier fraction. Hydrostatic forces are created during centrifugation to cause flow of the lighter fraction through the body into the other chamber. Preferably the surface of the separating body which faces the first chamber slopes away the spinning axis so that centrifugal force tends to dislodge any particles of the heavier fraction which might be lodged on the surface. The assembly of the present invention affords handling of blood for testing or analysis without human exposure to the blood components.