Da-An Gene Diagnostic Center, Sun Yen-Sen University of Medical Sciences, Guangzhou 510515 GD People's Republic of China

Hepatitis C Virus (HCV) and Hepatitis G Virus (HGV) remains the most important virus among those causing non-A non-B hepatitis. The detection of HCV and HGV RNA by nested Polymerase Chain Reaction (PCR) is believed to be the most reliable method to diagnose HCV and HGV infection. In this study, we developed a RT-PCR-ELISA method for semiquantitative detection of HCV and HGV RNA from serum samples. Sequences within the 5'-noncoding region of HCV and HGV are independently amplified in the presence of digoxigenin-11-dUTP and are detected by hybridization with biotinylated capture probes binding to a streptavidin-coated microtiter plate. Semiquantative enzyme-test DNA detection via chemiluminescence can be performed in a microtiter plate format. We were able to detect as low as 500-1000 genome equivalents per ml of serum, which is 10 times more sensitive than nested RT-PCR. Testing 65 non-A, non-B hepatitis patients blood samples, 46 were HCV RNA positive by RT-PCR-ELISA and RT-PCR (28%). Among 40 blood samples collected from intravenous drug abusers, the positive rates of HCV and HGV were 67.5% (27/40) and 40% (16/40) respectively by RT-PCR-ELISA. The results suggest that RT-PCR-ELISA is a sensitive and reliable method for HCV and HGV RNA detection and is possible to be used in clinical diagnosis of HCV and HGV infection.