Influence of Heparin and Calcium Chloride on Assay, Stability, and Recovery of Factor VIII

Abstract

The influence of heparin alone or in conjunction with calcium chloride on the coagulation assay for factor VIII, on the stability of factor VIII in blood and in plasma, and on the recovery of factor VIII in cryoprecipitate and in an intermediate purity concentrate was investigated. A stabilizing effect of heparin and calcium on factor VIII activity in blood and plasma could be confirmed. We were, however, unable to make use of the higher activity that can, under certain circumstances, be recovered in the cryoprecipitates; this was mainly due to the poor solubility of cryoprecipitates prepared from heparinized blood. Heparin (or the absence of a calcium chelator) also interferes with the recovery of plasma components other than factor VIII.

Influence of the Primary Anticoagulant on the Recovery of Factor VIII

“…These results have been substantiated by others [4,5]. We [2] and Morgenthaler et al [4] have also found that heparin, added to citrate plasma or when used as a pri mary anticoagulant, significantly stabilizes FVIII so that a two-phase decay does not occur.…”

“…We have previously reported that the FVIII level is considerably higher in heparinized plasma rather than citrated plasma with average values of 1.3 U/ml in heparin compared to 1.0 U/ml in citrate [2,3]. These results have been substantiated by others [4,5]. We [2] and Morgenthaler et al [4] have also found that heparin, added to citrate plasma or when used as a pri mary anticoagulant, significantly stabilizes FVIII so that a two-phase decay does not occur.…”

Studies on the Procurement of Blood Coagulation Factor VIII

“…This has important implications in the provision of plasma for large-scale production of factor VIII concentrates. How ever, in view of the initially disappointing results for bulk fractionation of heparinised plasma [8], large-scale stud ies will be required before a recommendation on the use of 0.5 CPD.A2 can be made.…”

Studies on the Procurement of Blood Coagulation Factor VIII in vitro Studies on Blood Components Prepared in Half-Strength Citrate Anticoagulant

“…However, in view of the disappointing results for bulk fractionation of hepa rinized plasma [17], similar large-scale studies will be required prior to any recommendation on the use of half-strength citrate anticoagulant. Recent studies on the fractionation of machine plasmapheresis plasma [46,47], containing around 16 mA/citrate, are encouraging.…”