An improved thaw-siphon method for the cryoprecipitate preparation.

Cryoprecipitates were prepared by various techniques including slow-thaw, rapid-thaw, thaw-centrifuge and thaw-siphon methods. Recoveries of 42.3 +/- 9.5% for slow-thaw, 48.8 +/- 8.8% for rapid-thaw, 41.3 +/- 15.8% for thaw-centrifuge and 67.4 +/- 8.9% for thaw-siphon in factor VIII activity were obtained. These results indicated that cryoprecipitate prepared by the thaw-siphon method had the best recovery of the factor VIII procoagulant activity. However, the final volume of the plasma was rather difficult to control and there was a risk that some factor-VIII-containing materials were siphoned with the cryo-poor plasma, especially approaching the end of the process. A modified thaw-siphon method was developed which involved stopping the siphon after 60 min, centrifuging and expressing the remaining plasma to a final volume of less than 15 ml. A yield of 67.1 +/- 9.8% factor VIII activity was obtained. This product is similar to that produced by the original thaw-siphon method in yield but about half in volume.