Quality control study on the performance of GB virus C/hepatitis G virus PCR

A novel virus, GBV-C/HGV, with a genome RNA organization similar to that of the Flaviviridae family was identified in sera of patients with hepatitis. The presence of GBV-C/HGV RNA can only be determined by the amplification of genomic regions using the reverse transcriptase-polymerase chain reaction (RT-PCR).

To assess the quality of the RT-PCR, 14 laboratories investigated a coded serum panel that comprised three GBV-C/HGV RNA-positive sera from three different patients, dilutions of these sera, and three GBV-C/HGV RNA-negative serum samples, two of which were collected from patients with hepatitis C but without GBV-C/HGV infection. In-house RT-PCR as well as commercially available GBV-C/HGV test kits were used in this study.

Only four laboratories (29%) reported the expected results, and four laboratories (29%) false-positive results; nine laboratories (64%) reported at least one false-negative result. Eleven laboratories (79%) detected the undiluted samples. The majority of false results were obtained with the dilutions of GBV-C/HGV RNA-positive samples. Negative results in the 10(-4) dilution were not considered to be false-negative, since during pre-screening GBV-C/HGV RNA had been detected in this dilution in only 50% of assays by the three laboratories involved in organizing the evaluation. Results obtained by commercial kits and by in-house assays were indiscriminate in quality of performance in this study.

To facilitate further quality assessment studies on the performance of GBV-C/HGV RNA detection, an international GBV-C/HGV RNA standard should be made available. Further efforts are required to optimize GBV-C/HGV RT-PCR.