BACTERIA LEVELS IN COMPONENTS PREPARED FROM DELIBERATELY INOCULATED WHOLE-BLOOD HELD FOR 8 OR 24 HOURS AT 20 TO 24-DEGREES-C

Background: An increase from 8 to 24 hours in the time that units of w hole blood can be held at room temperature after phlebotomy would give blood centers more flexibility in component manufacturing and might a llow receipt of many infectious disease test results prior to componen t preparation. However, the potential for bacterial growth during prol onged holding periods requires further study. Study Design and Methods : In the Phase I study, 2-unit pools of ABO-identical whole blood were deliberately inoculated on Day 0 with Staphylococcus aureus or Pseudo monas fluorescens. They were then divided in half and stored at 20 to 24 degrees C. Red cells (RBCs) with additive solution, platelet concen trates (PCs), and frozen plasma were prepared after 8 and 24 hours. Ba cteria levels in PCs and RBCs were monitored on Day 1; bacteria levels were measured in plasma after thawing. In the Phase II study, the sam e basic design as in Phase I was used, except that 10 bacterial specie s were studied, lower inocula were used, and RBCs prepared after a 24- hour room-temperature whole-blood hold were white cell-reduced by filt ration. Bacterial growth was monitored during 42-day storage of RBCs ( 1-6 degrees C) and 5-day storage of PCs (20-24 degrees C) and after th awing of frozen plasma. Results: For Phase I, significantly higher bac teria levels were observed in RBCs prepared after a prolonged hold (p< 0.05); higher levels were not observed in PCs and thawed plasma units. In Phase II, prior to white cell reduction by filtration, 8 of IO org anisms had significantly higher levels in RBCs prepared after a 24-hou r hold than in RBCs prepared after an 8-hour hold, when both were exam ined on Day 1 (p<0.05). For seven of eight organisms examined on Days 1, 21, and 42, filtration (white cell reduction) reduced the bacteria in RBCs prepared from 24-hour whole blood units to those levels found in unfiltered RBCs prepared from whole blood units held at 8 hours. A prolongation of the holding time from 8 to 24 hours resulted in signif icantly lower bacteria levels (p<0.05) in PCs early in storage (Days 1 , 1-2, or 1-3) for seven organisms, with no significant difference for two organisms, and a small but significant increase for one organism (Day 3, p<0.05). There was no difference in bacteria or endotoxin leve ls in thawed units of plasma prepared from whole blood after 8- or 24- hour holding times. Conclusion: The levels of bacteria present in comp onents after deliberately inoculated whole blood units are held for 8 and 24 hours depended on the organisms tested, the whole-blood holding period, and the blood component assayed; for RBCs, they also depended on whether WBC reduction by filtration was performed.