There are no critical reductions of the activities of clotting factors, inhibitors, and other important plasma proteins due to S/D treatment. Efficacy and safety of S/D plasma is not hampered by reduced activities of protein S and plasmin inhibitor. Dosage calculation and the evaluation of clinical response is simplified by usage of the more standardized S/D plasma compared to QFFP.

A reduction in the final citrate concentration of plasma collected by automated plasmapheresis results in higher yields of factors V, VIII, and IX without activation of hemostasis. More comprehensive studies should confirm previous work dealing with the establishment of the lowest citrate concentration acceptable in plasma used as therapeutic fresh-frozen plasma or as starting material for the manufacture of plasma derivatives.

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Background and objectives: The aim of this study was to determine the potencies of factor VII (FVII) and of activated FVII (FVIIa) in prothrombin complex concentrates (PCC). Materials and methods: We examined 56 lots of PCC from 5 manufacturers. Three brands were licensed preparations, and 1 product scries had been involved in thromboembolic complications. FVII and FVIIa were measured using a two-stage amidolytic assay and a specific clotting assay, respectively. We also quantified FVII clotting activity by a one-stage assay reflecting a mixture of FVII zymogen and FVIIa. Results: All PCC contained substantial amounts of FVII, and FVIIa could be detected in all lots. There were marked differences between manufacturers and some significant variabilities between batches. The two lots involved in thromboembolic events contained considerably more FVIIa than the PCC still licensed. The lowest FVIIa potencies were observed in an experimental product series, indicating that PCC can be produced without activation of FVII during the manufacturing process. Conclusion: FVIIa is present in all PCC containing FVII. High FVIIa potencies may contribute to the thrombogenic potential of these preparations, and determination of FVIIa potencies should be included in the in vitro characterization of PCC.

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