A test method for the absence of thrombogenicity in factor IX complex

Consumption coagulopathy was developed in three cases of liver cirrhosis and a case of haemophilia B upon administration of Factor IX preparations which had been tested by the manufacturers for the absence of active clotting factors according to the Japanese Minimum Requirements for Biological Products. By employing the TGT determination, however, active clotting factor(s) could be detected in some of the preparations used in these cases. Accordingly, it was found necessary to modify the current test method in the Minimum Requirements by introducing calcium ion into the test medium. There was no correlation between the clotting activitiy detected by our modified test method and the Factor IX potency of the product. Addition of heparin did not significantly influence the results in our modified method.