Initial evaluation of the Roche COBAS TaqMan HIV-1 v2.0 assay for determining viral load in HIV-infected individuals

Background: HIV type-1 (HIV-1) genetic diversity poses a challenge for the development of diagnostic tests based on nucleic acid amplification, which can be overcome, at least in part, by targeting multiple genomic regions. The new Roche Diagnostics COBAS TaqMan (CTM) HIV-1 v2.0 assay uses multiplex real-time PCR detection of sequences in the long terminal repeat and gag regions within the HIV-1 genome. Methods: We conducted initial comparative testing of HIV-1 viral load values in plasma samples from HIV-1-infected individuals using the Abbott RealTime HIV-1 (Abbott RT HIV-1), and the Roche CTM v1.0 and CTM v2.0 real-time PCR amplification systems, with a particular focus on patients previously undetectable or underestimated with the CTM v1.0 assay. Results: The new Roche CTM v2.0 assay showed excellent agreement with the other two assays over a wide dynamic range (r=0.9685). The assay also allowed accurate determination of viral load levels in individuals infected with HIV-1 isolates that were found falsely negative or underestimated with the Roche CTM v1.0 assay because of mutations within the gag region. Conclusions: The reliability and accuracy of the CTM v2.0 assay is similar to the Abbott RT HIV-1 assay. The implementation of a multiplex real-time PCR approach in the CTM v2.0 is a significant improvement in viral load testing in comparison with the CTM v1.0 assay.