Thaw-siphon technique for production of cryoprecipitate concentrate of factor VIII.

Plasma, which has been deep-frozen in plastic packs as flat slabs, is thawed in a 3-5 degrees C water-bath, and allowed to siphon continually into an attached satellite pack external to the bath. This thaw-siphon procedure is completed within 55-65 min and the cryoprecipitate, retained in the residual 25 ml of frozen plasma, contains 70-100% of the original plasma factor VIII. Clinical observations in haemophilic patients treated with these cryoprecipitates, have confirmed that the higher in-vitro content of factor VIII is associated with enhanced in-vivo effectiveness.