Comparison between the automated Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 test version 2.0 assay and its version 1 and Nuclisens HIV-1 EasyQ version 2.0 assays when measuring diverse HIV-1 genotypes in China

Background: Several commercially available HIV-1 viral load assays based on real-time detection technology and automated platforms are available. It is not clear how the diversity of HIV-1 genotypes impacts the ability to consistently detect HIV-1 viral loads. Objectives: To examine whether the diversity of HIV-1 genotypes impacts the ability of the Cobas AmpliPrep/Cobas TaqMan HIV-1 test version 2.0 (CAP/CTM v2.0), its version 1.0 (CAP/CTM v1.0) and the NucliSens EasyQ HIV-1 version 2.0 (EasyQ v2.0) assays to consistently determine the viral loads. Study design: The three assays were used to measure the viral load in 178 plasma samples with diverse genotypes from treatment-naive patients. Results: CAP/CTM v2.0 showed significant correlation and high agreement with CAP/CTM v1.0 and EasyQ v2.0. CAP/CTM v2.0 showed excellent detection of clade B samples compared with CAP/CTM v1.0 and EasyQ v2.0. However, significant differences were observed when using CAP/CTM v2.0 to test clade BC and AE samples. The HIV-1 load measured by CAP/CTM v2.0 differed by >0.5 log IU/ml in 59.52% and 72.62% of clade BC samples, and in 57.14% and 85.71% of clade AE samples, compared with CAP/CTM v1.0 and EasyQ v2.0, respectively. CAP/CTM v2.0 was more precise (13.18%) than EasyQ v2.0 (29.21%), and both assays showed good linearity (R >= 0.9926). Conclusions: The three assays may not deliver consistent results for samples belonging to clades BC and AE. It is strongly suggested that the version of the HIV-1 viral load assay used initially is also used at follow-up. (C) 2011 Elsevier B. V. All rights reserved.