Study on quantification of HBs-antibody by immunoradiometric assay

Quantification of HBs-antibody assay was carried out using a commercial assay kit and standard solutions of HBs-antibody recognised as 1st reference preparation of hepatitis B immunoglobulin by WHO. Standard curve of HBs-antibody was drawn with the function of 3D-spline and the correlation factor was obtained as r = 0.999. Coefficient of intra-assay variance was 3.8% and that of inter-assay variance was 7.8%. Dilution tests showed satisfactory results in the range of 2-16 times. Correlation between value of cut-off indices and concentration of HBs-antibody was obtained as the formula of y = 2.599 x-3.894 (r = 0.992) and 2.1 of cut-off index corresponded to about 5 mIU/ml of HBs-antibody concentration.