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