Comparison of quick and slow thaw methods of producing cryoprecipitate antihaemophilic factor from fresh and 24-hour-old blood

Abstract

SYNOPSIS Cryoprecipitate antihaemophilic factor concentrate was prepared from fresh and 24-hourold blood by quick and slow thaw methods. Recovery of factor VIII was greater by the slow thaw method and there was less loss into the supernatant plasma. Cryoprecipitate produced from fresh blood contained more factor VIII than that produced from 24-hour-old blood so that the most potent concentrate was produced from fresh blood by the slow thaw process. An adequate therapeutic preparation was, however, produced by the slow thaw method using 24-hour-old blood and it is suggested that this procedure could be adopted in order to supplement supplies.Haemophilic blood is deficient in antihaemophilic factor (factor VIII), a deficiency which can be partially corrected by transfusions of fresh frozen plasma or, more effectively, by plasma fractions containing high concentrations of antihaemophilic factor. Until recently the preparation of concentrated antihaemophilic factor from animal or human blood involved large-scale fractionation processes which were beyond the scope of most hospital laboratories and blood transfusion centres. In 1965 Pool and Shannon described a simple cold precipitation method for the production of antihaemophilic factor concentrate which does not require such elaborate equipment. Cryoprecipitate antihaemophilic factor is now an established therapeutic material but its effectiveness and ease of administration have led to a steadily increasing demand. It was therefore considered desirable to examine various techniques for the preparation of cryoprecipitate in order to determine those which are the simplest, most convenient, and yet effective.The original method of Pool and Shannon (1965) is based upon the fact that when plasma is frozen and allowed to thaw slowly at + 4°C the antihaemophilic factor remains as a precipitate which can be separated by centrifugation. Using a closed double plastic bag system the blood is processed under aseptic conditions thus allowing recovery of both the cryoprecipitate and the antihaemophilic

Principles of in vivo Recovery and Survival Studies

“…With appropriate timing, this number can be reduced to 8. The first four (before, 10-15, 30, 60 rnin post-infusion) allow the determination of the maximum level of circulating VIII:C; the last four (4,12,24,36 or 48 h post-infusion) allow the calculation of the VIII:C biological half-life. According to various studies, the peak VIII:C plasma level can be achieved immediately or within 15 minutes after the end of infusion In some studies only one sample (either immediate or 30 or 60 rnin post-infusion) is drawn and tested as assumed maximum VII1:C level (Smith et al, 1972;Nilsson and Hedner, 1977).…”

Preparation of Improved Cryoprecipitated Factor VIII Concentrate

“…In contrast, the second phase of decay was associated with a very long half-life. If cryoprecipitation causes a constant propor tion of the starting plasma VIII:C to appear in the precipitate, the use of very fresh plas ma as starting material should give higher VIII.C yields [3,9]. slow-thaw counterparts, while one group, ACD/18 h plasma, showed a superior VIII:C yield in the slow-thaw group over the rapid-thaw equivalent.…”

Evaluation of the ‘Mason’ (Continuous‐Thaw‐Siphon) Method for Cryoprecipitate Production

“…Early work demonstrated that faster thawing could increase the factor VIII content of cryoprecipitate [3]. At the time there was not full agreement on this [4] but subsequent studies have confirmed the original observation [5-71.…”