Among 6684 HBsAg-positive samples, 615 were subjected to an 'in-house' HBsAg neutralization test (NT). Of these, 91 (100%) high-reactive samples (optical density [OD] 1.000-3.000) and 286 (93%) of 289 low-reactive samples (OD<1.000) were neutralized, and 235 (100%) grey-zone reactive samples were 'in-house' NT negative. Eighty-four samples of varying reactivities that were tested by the 'in-house' NT were compared with a commercial NT (AxSYM, Abbott).