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In routine blood bank production of single-donation cryoprecipitate, the introduction of a 16-hour hold at 4 degrees C, with the frozen plasma units packed into polystyrene containers, resulted in plasma prethaw temperatures of -4 degrees C to -8 degrees C. This in turn resulted in cryoprecipitate fibrinogen levels that were 214 percent of those obtained when units were thawed immediately after removal from -30 degrees C storage. In scale-model production of factor VIII concentrate, plasma warmed from -30 to -10 to -15 degrees C over 18 hours before pooling and thawing yielded cryoprecipitate fibrinogen levels that were 66 percent of those found in plasma warmed to -2 to -5 degrees C over the same period. Processing -30 degrees C plasma without a warming period led to cryoprecipitate fibrinogen levels that were 40 percent of those obtained from plasma warmed to -2 to -5 degrees C. These differences were accentuated after purification of the cryoprecipitates to an intermediate-purity factor VIII concentrate. These results suggest that simple modifications in production methods allow the fibrinogen content of cryoprecipitate to be tailored to specific uses.

The licensed balanced salt solution Plasma-Lyte, buffered with a clinical solution of sodium bicarbonate, was evaluated as a suspending fluid for platelet concentrates. Platelets suspended in this medium showed better pH maintenance over 5 days of storage compared to platelets stored in plasma (7.0 vs 6.45, P < 0.001). This was reflected in improvements in in-vitro indicators of platelet viability-hypotonic shock response (79 vs 48%, P < 0.05), aggregation to paired agonists (86 vs 62%, P < 0.05); and platelet size distribution (104 vs 119%, P < 0.001). Dissolved bicarbonate measurement showed less depletion of bicarbonate in the synthetic medium compared to plasma, which suggests a lower rate of lactate formation. A synthetic medium containing dextrose showed inferior platelet storage characteristics when compared to the plasma-lyte/bicarbonate medium in a paired study (Day 5, pH 6.53 vs 6.9, P < 0.05). The results suggest that utilization of substrates other than dextrose allows platelets to metabolize without the accumulation of lactate that leads to pH drops during storage in plasma, and continue to support the feasibility of storing platelets in a non-plasma environment.

SummaryWe have attempted to exploit the Ca2+ -dependent stability of factor VIII in producing factor VIII concentrates of higher yield. Plasma levels of ionised calcium were increased in two ways: (a) whole blood collection into half-strength citrate CPD anticoagulant, leading to free Ca2+ levels of ca 120 µM and (b) apheresis collection of plasma which was then recalcified to free Ca2+ levels of ca 300 µM under heparin cover. Coagulation factor concentrates were prepared using model versions of our industrial scale manufacturing methods. Factor VIII yield was increased through low citrate collection. This did not compromise factor IX yield or thrombogenic potential. Use of recalcified heparinised plasma did not lead to any improvement in factor VIII yield and resulted in a marked drop in factor IX recovery, possibly from interference by heparin of factor IX binding in ion-exchange chromatography. The benefits accruable through the use of half-strength citrate CPD anticoagulant support the continued evaluation of this preservative in large scale blood collection and fractionation. The deleterious effects of heparin in charge-mediated plasma fractionations may pose serious difficulties in harvesting vitamin K dependent factors.

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