Five assays for anti-HBs were compared to improve potency test of Human lgG preparations. The three commercial EIA kits were optimized including dose response curve ranges and compared by conducting a co-laboratory study. After selecting the most reproducible EIA kit, methods comparison was performed with 22 samples in 5 different days. As a result, EIA (7.7 ${pm}$ 5.3%) and MEIA (AxSYM: 3.7 ${pm}$ 1.9%, IMx: 1.6 ${pm}$ 0.8%) showed precision and accuracy (100.1 ${pm}$ 12.6%). Therefore, the validated EIA assay was established and it is believed to be comparable to current MEIA.