DETECTION OF ANTI-HCV ANTIBODIES IN IMMUNOGLOBULIN PREPARATIONS BY RECOMBINANT IMMUNOBLOT ASSAY

The presence of anti-HCV antibodies in immunoglobulin preparations was investigated by recombinant immunoblot assay (RIBA) and enzyme immunoassay (EIA). While EIA was found to be suitable for detecting anti-HCV antibodies in immunoglobulin preparations, the RIBA could not be used without modifying the standard procedure developed for use with human sera. The two modifications were: (1) incubation with the anti-human IgG conjugate in a single test tube for each strip, instead of in a common vessel, (2) removal of the conjugate after 15 min and its replacement with fresh conjugate for a second 15 min incubation period. Thirty-six immunoglobulin preparations were tested using this modified procedure. Twenty-nine out of 31 (93.5%) preparations received in 1992 were anti-HCV positive, whereas the five immunoglobulin preparations received in 1993 were negative. These results were compared with those obtained on the same samples with the EIA. The percentage of samples positive with EIA was 74.2%. The difference between the results obtained with modified RIBA and EIA was statistically significant (P < 0.05). © 1994 by Academic Press, Inc.