Storing platelets in an additive solution containing magnesium and potassium improves the functionality of the platelets, as measured by in vitro testing, and may allow a reduction of the amount of plasma required to be carried over to the final unit.

The growth of Yersinia enterocolitica in AS-1 red cells was investigated so as to study the organism's proliferation kinetics and to evaluate the effect of prestorage white cell (WBC) reduction on bacterial multiplication. Twenty-four 2-unit pools of ABO-compatible whole blood were prepared and inoculated with Y. enterocolitica to final concentrations ranging from 0.3 to 132 organisms per mL. After inoculation, pools were split equally, AS-1 red cells were prepared, and 1 unit of each pair (test unit) was WBC-reduced with a WBC-reduction filter. Quantitative bacterial cultures of both WBC-reduced and control units were performed at several points throughout preparation and storage. Less than 10 percent of the inoculated organisms was recovered from blood samples taken after a 7-hour room-temperature holding period. By the end of 42 days of storage, Y. enterocolitica was recovered from unfiltered red cells in 2 of the 6 units inoculated at the lowest levels (0.3 and 0.7 organism/mL), from 8 of the 12 units inoculated at the intermediate levels (2.8, 5.2, 30.7, and 43 organisms/mL) and from 6 of the 6 units inoculated at the highest levels (98.8 and 132 organisms/mL). Positive cultures were seen as early as Day 7. In contrast, filtered units inoculated at all levels less than or equal to 98.8 organisms per mL (21/21 units) were sterile at the end of the 42-day storage period, while 2 units (2/3) inoculated at 132 organisms per mL showed growth despite filtration.(ABSTRACT TRUNCATED AT 250 WORDS)

Rather than increasing the risk of bacterial proliferation through removal of active phagocytic cells, WBC reduction by filtration before blood storage may act to reduce the likelihood of significant bacterial proliferation, possibly by removal of microorganisms along with WBCs.

PEN110-treated RBCs stored for 28 days meet all critical requirements for therapeutically useful units.

RBC and PLT in vivo variables, and most in vitro variables, were not significantly different after storage with WB holding times of 8 and 24 hours except for a slight diminution of RBC recovery with the 24-hour hold after 42 days of storage.