Figure 1.

Schematic section of a hollow fiber for plasma exchange. Whole blood flows lengthwise along the interior of the fiber, whereas its plasma components, such as Igs, clotting factors, fibrinogen, and albumin, pass through the pores in the fiber wall and collect outside the fiber. The wall of the hollow fiber functions as the separating membrane with a pore size that allows penetration by plasma but not by the blood’s cellular components (red blood cells [RBCs], white blood cells [WBCs], and platelets).