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. CI1 h was calculated after 353 transfusions (67 patients), and CCI1 h, after 195 transfu‐sions (55 patients), with pretransfusion PLT counts of not greater than 20 × 109 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 × 109 per mL. Routinely produced LR‐PCs had a volume of 282 ± 15 mL (n = 10,193) and contained 329 × 109± 40 × 109 PLTs (n = 3467). For 7‐day‐old LR‐PCs, 76 of 78 (97%) of the transfusions resulted in a CI1 h of at least 10 and 37 of 39 (95%) in a CCI1 h of at least 7.5, which indicated levels for successfulness. Mean ± SE values of CI1 h and CCI1 h 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 CI1 h and CCI1 h 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.