In vivo PLT increments after transfusions of WBC-reduced PLT concentrates stored for up to 7 days

BACKGROUND: Bacterial screening and improvement of storage conditions of leukoreduced PLT concentrates (LR-PCs) allows extension of their storage period from 5 to 7 days. STUDY DESIGN AND METHODS: For in vitro studies, 40 LR-PCs made from five buffy coats and plasma were studied for 8 days. For in vivo studies, routinely produced LR-PCs stored for 2 to 7 days after blood collection were administered to clinically stable thrombocytopenic patients. Cl-1h was calculated after 353 transfusions (67 patients), and CCl1h, after 195 transfu-sions (55 patients), with pretransfusion PLT counts of not greater than 20 x 10(9) per mL. RESULTS: Storage experiments showed that the pH of LR-PCs remained greater than 6.8 for 8 days, provided that the PLT concentration was less than 1.3 x 10(9) per mL. Routinely produced LR-PCs had a volume of 282 +/- 15 mL (n = 10,193) and contained 329 x 10(9) +/- 40 x 10(9) PLTs (n = 3467). For 7-day-old LR-PCs, 76 of 78 (97%) of the transfusions resulted in a Cl-1h of at least 10 and 37 of 39 (95%) in a CCl1h of at least 7.5, which indicated levels for successfulness. Mean +/- SE values Of Cl-1h and CCl1h of 7-day-old LR-PCs were 28.7 +/- 2.3 (n = 78) and 19.0 +/- 2.0 (n = 39), respectively. No significant differences were observed between 5- and 7-day-old LR-PCs transfused with respect to Cl-1h and CCl1h values. CONCLUSION: In vitro and in vivo studies showed that LR-PCs can be stored for up to 7 days with excellent clinical results, provided that they are routinely screened for bacterial contamination.