Hepatitis B-type virus (HBV) screening at Japanese Red Cross Blood Centers is carried out by agglutination method. The risk of post-transfusion hepatitis B (PTHB) has markedly decreased, especially since the hemagglutination inhibition test (HI) for anti-HBc and the passive hemagglutination test (PHA) for anti-HBs were introduced to screening in addition to the reversed passive hemagglution test (RPHA) for HBsAg in 1989. However, PTHB had not been completely eliminated even using the current system (RPHA, HI & PHA) which is rather complicated and time-consuming. We therefore evaluated the PRISM-HBsAg assay (Abbott), a fully automated assay based on chemiluminescence technology, in comparison with EIA-HBsAg (Auszyme overnight protocol, Dainabot) and our present HBV system.
Sensitivity of PRISM-HBsAg (0.08ng/ml in ad panel and 0.06ng/ml in ay panel) was higher than that of EIA-HBsAg (0.23ng/ml in ad panel and 0.11ng/ml in ay panel). In 87 HBV-DNA-positive panels that were RPHA-negative (or weakly positive) and HI-positive, 59 and 50 were positive with PRISM-HBsAg and EIA-HBsAg, respectively.
A total of 20, 041 donor specimens were tested simultaneously by PRISM-HBsAg, EIA-HBsAg and RPHA. The number of disqualified samples was 98, 91, 71 and their determination ratio (disqualified samples/initially positive samples×100) was 96.1%, 20.8% and 19.7%, respectively. These results show that the determination ratio of PRISM-HBsAg assay is clearly higher than that of EIA-HBsAg and RPHA. There were 19 RPHA-negative and PRISM-HBsAg-positive samples, 17 of which were HI-positive and disqualified according to the criteria of our present HBV system. Of 313 samples disqualified because of their high HI titer despite their negative PRISM-HBsAg and EIA-HBsAg, 10 were PCR-positive with DNA preparation concentrated from 10ml samples. These results indicate that the sensitivity and specificity of RPISM-HBsAg assay are significantly higher than those of EIA-HBsAg and RPHA. However, anti-HBc screening is still necessary, because some HBV-DNA-positive samples with high anti-HBc activity are PRISM-HBsAg-negative.
