A Standardized Technique for Efficient Platelet and Leukocyte Collection Using the Model 30 Blood Processor

Abstract

The Model 30 Blood Processor is a safe and simple means of harvesting blood cell components. Presently cell collection depends on a visual assessment by the operator of the indistinct boundaries of cell fractions. To determine when each cell component could best be harvested, serial samples were taken from the output port at fixed intervals and the results of counts and differentials were graphed and tabulated. Studies in normal donors were done using acid-citrate-dextrose (ACD), 2% sodium citrate in 6% hydroxyethyl starch (HES), or heparin as anticoagulants. There was considerable overlap between the latter part of the platelet band, the leukocyte band and the rising hematocrit with all 3 anticoagulants. Normally functional lymphocytes could be harvested efficiently (.apprx. 80%) using ACD or heparin. Platelets could be harvested from ACD very efficiently (.apprx. 90%). Granulocytes could not be harvested from ACD (< 10%) since they were dispersed in the red blood cell (RBC) layer. Using HES, granulocytes could be harvested efficiently (.apprx. 70%) by extending collection into the RBC layer. Based on these data, a standard technique for cell collection was devised. The flow rate is slowed to 20 ml/min and collection is carried 30 ml (90 s at a rate of 20 ml/min) for platelets. The RBC loss is approximately 6-8 and 2-3 ml/pass, respectively. The Model 30 is a highly efficient apparatus for blood cell separation but the volume of blood processed is limited by the intermittent blood flow.