RESUMO
BACKGROUND: Positive rate of HCV RNA in anti-HCV immunoblot indeterminate samples from Korean blood donors was investigated in this study. Futhermore, reactivity of enzyme immunoassay kits was evaluated according to patterns of band reactivity and RNA positivity of indeterminate samples. METHODS: HCV RNA was tested from a total of 180 samples that had been repeatedly reactive to LG HCD 3.0 or DONG-A HCV 3.0 and further confirmed to be indeterminate by LG HCD CONFIRM at 14 Korean Red Cross Blood Centers in 1997. Correlation between HCV RNA and reactivity to each recombinant antigens was analysed. Three kinds of EIA kits such as HCD 3.0, DONG-A HCV 3.0 and Cobas Core Anti-HCV EIA kits were tested of their reactivity to 56 samples that had shown single band positivity on LG HCD CONFIRM. RESLUTS: HCV RNA was detected in 11 (6.1%) of 180 samples. Positivity of 897 band showed positive correlation with HCV RNA positivity (p<0.001), while Core518 showed negative correlation (p<0.001). DONG-A HCV 3.0 showed negative reaction to two samples with anti-897 specificity and HCV RNA, while LG HCD 3.0 and Cobas Core HCV showed negative reaction to one sample with anti-EIE2NS4 and HCV RNA. CONCLUSION: Positive rate of anti-HCV immunoblot indeterminate samples from Korean blood donors was 6.1%. In case of indeterminate results by LG HCD CONFIRM, positive reaction to 897 band highly suggests the presence of HCV RNA, while Core518 the absence of HCV RNA. It is highly recommended that specificity of Core518 antigen be increased in LG HCD 3.0 or LG HCD CONFIRM and sensitivity of recombinant antigen from the 3rd non-structural region of HCV genome be increased in DONG-A HCV 3.0.