- Lymphapheresis: This procedure is done to collect large numbers of white blood cells (lymphocytes). Blood is collected through a needle in an arm vein, similar to donating blood. The blood is separated it into its components by centrifugation (spinning), the white cells are removed, and the rest of the blood (red cells, plasma and platelets) is returned to the body, either through the same needle or through another needle in the other arm.