Usefulness of Anti-HCV ELISA Test and HCV Reverse Transcriptase-PCR for the Diagnosis of Hepatits C Viral Infection

Abstract

BACKGROUND: The diagnosis of hepatitis C virus (HCV) infection is screened by anti-HCV enzymelinked immunosorbant assay (ELISA) and confirmed by recombinant immunoblotting assay (RIBA) or HCV RT-PCR. We attempted to evaluate the results between anti-HCV ELISA and a qualitative HCV RT-PCR.METHODS: Four hundred and twenty patients who were tested with anti-HCV ELISA and HCV RTPCR, simultaneously, from January 2002 to June 2005 were enrolled in this study. Anti-HCV ELISA was performed by AxSYM HCV version 3.0 (Abbott Laboratories, USA). HCV RT-PCR was performed using in-house RT-nested PCR methods from January 2002 to October 2004 and HCV Genotype Amplification Kit (LiPA) (Bayer Healthcare, USA) from November 2004 to June 2005.RESULTS: Of the 420 patients tested, 321 were positive for anti-HCV ELISA, and 204 were positive for RT-PCR. The positive predictability of anti-HCV ELISA was 63.6%. Among anti-HCV positive patients, RT-PCR was positive in 7.3% of the patients with sample/cut-off (S/CO)<6, compared with 82.8% of the patients with S/CO>/=6. Among the 117 patients with positive anti-HCV, but with negative HCV RT-PCR, 64 had liver diseases such as chronic hepatitis C, chronic hepatitis B, or hepatocellular carcinoma. Twelve patients showed positive HCV RT-PCR, but negative anti-HCV results; of these 9 had hepatic dysfunction.CONCLUSIONS: In the patients who were positive for anti-HCV ELISA with a low S/CO, HCV RT-PCR positivity was shown in a low proportion. Therefore, in such cases, the results should be confirmed by RIBA or HCV RT-PCR. The liver function test showed increased levels of hepatic enzymes in patients with positive HCV RT-PCR, but negative anti-HCV. Such findings correlate to an early phase of chronic hepatitis C, suggesting the necessity of continuous follow up.