A collaborative study to establish a Korea National Biological Standard for antithrombin III concentrate

Abstract number: CD013

Kang H. N., Lee S. H., Kim S. N., Hong C. M., Lee K. H., Oh H. J., Yoo S. H., Shin I. S., Choi S. E., Lee S. H., Hong S. H.

Republic of Korea

We have carried out collaborative study to evaluate a preparation of antithrombin concentrate whether or not it was suitable to serve as the candidate for a Korea National Biological Standard. Six laboratories, including three manufacturers and three National Control Laboratories, participated in this study. The potency of this candidate preparation was determined using the heparin cofactor chromogenic method. The method is described in the Minimum Requirements for Biological Products and the European Pharmacopoeia. The candidate gave excellent intra- and interlaboratory correlation when assayed against the Second International Standard for Antithrombin Concentrate, coded as 96/520. The participants contributed data from a total of 90 independently assays and the results were accepted as statistically valid when the outcome of the analysis was for linearity of dose-response relationships and for intersection at a common point at zero dose in slope-ratio model. Combined potency estimates were obtained by taking geometric means of results from all assays at each laboratory, and overall potency estimates were calculated as unweighted geometric means of results from all laboratories. The results were expressed in the form of histograms and 95% confidence intervals. Based on the results of the collaborative study described here, the candidate reference standard is judged to be suitable to serve as the Korea National Biological Standard for antithrombin concentrate with the following potency (IU/vial): 51.9 IU/vial (95% confidence intervals = 48.24–55.98 IU/vial).