Evaluation of the 'Mason' (continuous-thaw-siphon) method for cryoprecipitate production.

A comparison was made of the factor VIII recovery in cryoprecipitate made by the continuous-thaw-siphon technique of Mason [1], by our routine method of overnight thawing at 4 degrees C and by a fast-thaw method. The siphon method resulted in a mean recovery of 71% of the factor VIII. This is at least double the yield obtained by the routine method and could not be solely attributed to the faster processing as cryoprecipitate prepared by the fast-thaw method gave a factor VIII yield of 53%, which was significantly less than the Mason product. This product also contained increased amounts of factor VIII-related antigen and fibrinogen. Characterisation of the thaw-siphon cryoprecipitate factor VII by gel filtration, electrophoretic mobility, stability and measurement of isoagglutinin titre did not reveal any significant qualitative differences from cryoprecipitate produced by other methods.