A collaborative study to establish a Korean standard for factor VIII : C concentrate

Abstract number: CD012

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

Republic of Korea

A collaborative study among five laboratories including three manufacturers and two national control laboratories was carried out to evaluate the suitability of a candidate to serve as a Korean Reference Standard for Factor VIII:C concentrate.

Materials and methods  

Two approaches were been attempted to determine the potency of this candidate. The one is an one-stage clotting assay and the other is a chromogenic assay. To achieve acceptable precision and accuracy, the following recommendations by the International Society on Thrombosis and Haemostasis were adopted in the assays; e.g. pre-dilution of samples in Factor VIII (FVIII)-deficient plasma, inclusion of 1% albumin in the dilution buffer and calibration against the 6th International Standard for the blood coagulation Factor VIII : C concentrate, coded 97/616. There were good agreements in the data collected within each laboratory and among laboratories for both assays employed here, in the calibration of the candidate preparation against the International Standard. The overall potencies by the one-stage clotting assay and the chromogenic assay, however, were not in very good agreements between them. Each differed from one another in that the potency obtained from chromogenic assay was approximately 17% lower than that from one-stage clotting assay. The estimated geometric mean value obtained by the one-stage clotting assay was 8.4 IU per vial, and that by the chromogenic assay was 6.7 IU per vial. Based on the results of this collaborative study, the candidate reference standard is judged to be suitable to serve as a Korean Reference Standard for Factor VIII:C concentrate.