Method Verification of Factor VIII Potency Test by Chromogenic Assay
Keywords:
Factor VIII, Chromogenic assay, Method VerificationAbstract
Factor VIII is an essential blood-clotting glycoprotein which is a cofactor for activating factor IX to an active form and then reacts to factor X for initiating the blood coagulation system. The aim of this study was to verify the potency test of Factor VIII products by chromogenic assay according to the European Pharmacopoeia recommendation. The results of linearity suggested that the appropriate concentrations for this assay were in the range of 0.000625 - 0.005 IU/ml. The percentage recovery geomean of accuracy test was 84.48-109.35%. The coefficient of variation (CV) of precision; within run, between run and reproducibility were 11.57, 10.84 and 7.74, respectively. The analysis of other plasma products by the verified method showed the technique was specific to Factor VIII. In addition, the determination of potency of Factor VIII products (11 lots of product A and 6 lots of product B) by the verified method found that both products complied with the European Pharmacopoeia specifications. The comparable results to the manufacturer’s test showed that the potency results were significantly different in product A but not in product B. However, the manufacturer for product A used the method and reference standard which were dissimilar from this study. In conclusion, the potency testing of Factor VIII by chromogenic microplate assay is suitable as a standard method at laboratory of the Institute of Biological Products.
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