The Correlation between the S/CO Ratio of Anti-HCV ELISA, and the Results of the RIBA and RNA Test / 대한수혈학회지

BACKGROUND: Recombinant immunoblot assay (RIBA) or RNA test is considered to be a supplemental test for confirming a HCV infection. A correlation has been reported between the signal-to-cutoff (S/CO) ratios of a third generation HCV enzyme-linked immunosorbent assay (ELISA) and a confirmed HCV infection. This study examined the results of an evaluation of domestic anti-HCV EIA and immunoblot kit (RIBA) in Korean donors. METHODS: A total of 375,576 donor samples were tested for anti-HCV using the LG third generation HCV ELISA (LG HCD 3.0 TMB, LGphD, Korea) and HCV RNA by NAT (Biomerieux/Roche RT-PCR, 24 pool). The anti-HCV repeat reactive samples were further tested by third generation RIBA (LG HCD Confirm, LGphD, Korea). A positive result by either the nucleic acid amplification test (NAT) or RIBA was interpreted as a confirmed HCV infection. RESULTS: There were 506 out of the 375,576 donor samples (0.13%) that were anti-HCV repeat reactive (RR) by routine screening ELISA. The confirmed HCV prevalence in the donors was 0.01% (RIBA 42/375,570, RNA 36/375,570). 443 samples from the 506 repeat reactive samples in ELISA (87.6%) showed a S/CO ratio 3.6 (mean 4.40+/-0.80), compared with the negative group (mean 1.54+/-0.64). CONCLUSION: There was a good correlation between a high S/CO ratios and a confirmed HCV infection. In addition, samples showing a low S/CO ratio with an ID (Indeterminate) or negative RIBA result suggest a high probability of nonspecific reactivity in ELISA.

Hepatitis C Virus Infection in Pregnancy / 대한산부인과학회잡지

OBJECTIVE: Our purpose was to estimate the prevalence of hepatitis C virus seropositivity and define the risk factors for HCV infection in a group of pregnant women and the effect of HCV infection to mother and baby at the time of delivery. METHODS: From March 1997 to February 1998, 5655 women who delivered over 20 gestational weeks at our hospital were screened for HCV-Antibody(RIA), and the samples of most of HCV-Ab positive cases were analyzed for HCV-RNA by polymerase chain reaction(PCR). We also studied the risk factors for HCV infection, the effect of HCV infection to mothers and neonates at delivery. RESULTS: Of 5655 mothers 25 (0.44%) were HCV-Ab positive, and 20 of HCV-Ab positive mothers were analyzed for HCV-RNA by PCR. Of 20 HCV-Ab positive mothers 12 cases (60%) were HCV-RNA positive. Risk factors significantly more prevalent among HCV-seropositive patients were : a history of habitual intraveneous drug use, a history of smoking, alcohol drinking during pregnancy, having liver cirrhorsis. The proportions who had received a blood transfusion, had a history or ongoing syphilis or were positive for hepatitis B virus surface antigen were not significantly different between seropositive and seronegative women. Liver function test at delivery was abnormal in 4 cases(16%) of HCV-Ab positive group. And the number of abnomal liver function test cases in HCV-Ab negative group were 47(0.83%). This had statistical difference. In neonates at delivery, all 20 neonates of 20 ones having HCV-Ab positive mother were HCV-Ab positive. But only 2 cases of 20 babies were HCV-RNA positive. CONCLUSION: Mothers who have risk factors such as injecting drug use, smoking, alchohol drinking and liver cirrhorsis, should undergo HCV-Ab testing and quantitative HCV-RNA testing by PCR. More advanced studies about vertical transmission of HCV infection are needed.