A comparison of centrifugal and membrane-based apheresis formats.

Membrane and centrifugal apheresis operate on different physical principles but are both capable of efficiently fractionating plasma proteins from whole blood. For therapeutic purposes, both formats yield about the same protein clearance per liter of solute exchanged and neither is significantly more rapid than the other. Only continuous centrifugation can be used to pherese cellular elements and only membrane filter can be deployed in 'spontaneous' circuits. Hardware for continuous centrifugation is more expensive and disposables less expensive than for the membrane methods; the 'crossover' occurs at 200 treatments. To date, only the centrifugal method is employed for donor apheresis; this may change in the future as membranes can yield a truly platelet-free product and appear to offer a much more rapid collection cycle.