Coagulation in an Agarose Gel and its Application to Detecting Factor VIII Clotting Activity Associated with Factor VIII-Related Antigen

The coagulation of citrated plasma in an agarose gel treated with thrombin or calcium chloride may be detected by a change in the gel opacity. Experimental evidence suggests that this opacity represents fibrin formed within the gel matrix. The coagulation of citrated 0% factor VIII haemophilic plasma in an agarose gel treated with calcium chloride is delayed compared with normal plasma. A method for detecting factor VIII clotting activity in agarose has been developed based on factor VIII promoting the coagulation of haemophilic plasma in agarose.

Using this test to detect factor VIII clotting activity in a one dimensional Laurell electroimmunoassay for factor VTII-related antigen, all factor VIII clotting activity detected is found in the same position as the factor VIII-related antigen immunoprecipitate. This result suggests that the molecule containing factor VIII clotting activity carries factor VIII-rolated antigen determinants.