Hepatitis C virus quantitation: Optimization of strategies for detecting low-level viremia

A long-term assessment of quantitative hepatitis C virus (HCV) testing was performed at the University of Pittsburgh Medical Center. The Quantiplex HC V RNA 2.0 branched-chain DNA (bDNA) assay (Bayer Diagnostics) for hepatitis C viral load determination was used to test 3,471 specimens. bDNA-negative samples were also tested by an in-house qualitative reverse transcriptase (RT)-PCR assay with a measured sensitivity of fewer than 100 HCV genome equ ivalents per milliliter. Of 1,239 bDNA-negative specimens, 74.1% were negat ive and 25.9% were positive by RT-PCR indicating the presence of viremia in a significant proportion of bDNA-negative samples. We discuss the medical and economic implications of these results and propose two alternatives for clinical laboratories to consider in approaching quantitative HCV testing. For laboratories able to perform a sensitive RT-PCR assay for less than or equal to 40% of the bDNA test cost, prescreening bDNA requests by RT-PCR m ay be the most cost-effective approach.