Comparison of the Abbott m2000 HIV-1 real-time and Roche AMPLICOR monitor v1.5 HIV-1 assays on plasma specimens from Rakai, Uganda

Summary: The need for viral load (VL) monitoring of HIV patients receiving antiretroviral therapy (ART) in resource-limited settings (RLS) has become apparent with studies showing the limitations of immunological monitoring. We compared the Abbott m2000 Real-Time (Abbott) HIV-1 assay with the Roche AMPLICOR Monitor v1.5 (Roche) HIV-1 assay over a range of VL concentrations. Three hundred and eleven plasma samples were tested, including 164 samples from patients on ART ≥ six months and 147 from ART-nai{dotless}̈ve patients. The Roche assay detected ≥400 copies/mL in 158 (50.8%) samples. Of these, Abbott produced 145 (91.8%) detectable results ≥400 copies/mL; 13 (8.2%) samples produced discrepant results. Concordance between the assays for detecting HIV-1 RNA ≥400 copies/mL was 95.8% (298/311). The sensitivity, specificity, positive predictive value and negative predictive value of Abbott to detect HIV-1 RNA ≥400 copies/mL were 91.8%, 100%, 100% and 92.2%, respectively. For the 151 samples with HIV-1 RNA ≥400 copies/mL for both assays, a good linear correlation was found (r = 0.81, P<0.0001; mean difference, 0.05). The limits of agreement were -0.97 and 1.07 log₁₀ copies/mL (mean±2 SD). The Abbott assay performed well in our setting, offering an alternative methodology for HIV-1 VL for laboratories with realtime polymerase chain reaction (PCR) capacity.