The elimination of hydroxyethyl starch (HES) from donor blood was studied following either single or multiple intermittent‐flow centrifugation leukapheresis. Immediately following pheresis, serum HES concentrations fell rapidly. The rate of elimination then slowed with trace amounts of HES persisting for weeks. Pharmaco‐kinetic analysis using a two‐compartment open model revealed an average distribution half‐life and terminal half‐life of 3.84 and 48 days, respectively. After multiple phereses, HES accumulated in serum. Although the pattern of elimination was similar, the persistence of HES was more protracted, with the serum level predicted to reach the baseline at 72 weeks pastpheresis versus 38 weeks after a single pheresis. The importance in regards to toxicity, if any, of the persistence of trace amounts of HES in donor blood is presently unknown.

Ten normal donors were monitored before, during, and after ten weekly donations of platelet concentrates prepared using the Haemonetics Model 30 blood processor. Analysis of these data indicates about a 20 per cent decrease of lymphocytes, with B cells being significantly decreased in half of these patients. While coincident immunoglobulin deficiencies did not develop in this short-term study, it is presumed that these would occur with a prolongation of platelet donations, as has been noted in previous studies. Additional studies are indicated to further delineate the lymphocyte depletion in normal platelet donors.