One hundred and twenty reactive sera were selected from specimens studied by enzyme immunoassay (EIA, Abbott Laboratories, Abbott Park, North Chicago, IL) for antibodies against human immunodeficiency virus (HIV-1). Using these sera, the 'WesPage' system (American Bionetics, Inc., Haywood, CA), was compared to the Western blot evaluation performed by a commercial reference laboratory (Abbott Laboratories, Abbott Park, North Chicago, IL). Using criteria established by the Food and Drug Administration, all major bands representing specific antigens of HIV-1 and their corresponding antibodies were identified on the immunoblot membrane when the strongly reactive control serum was used in the assay. The weakly reactive control serum demonstrated antibodies to the p24 core antigen and the gp120/160 envelope antigen of the virus in addition to others. The non-reactive control serum did not react with any antigen on the immunoblot sheet. All results obtained by our evaluation agreed with the reference laboratory results. The WesPage assay offers a combination of advantages which include rapid turn around time, less direct contact with potentially infectious materials, good resolution of bands and high reproducibility of results.