Evaluation of the Abbott m 2000 RealTi m e Human Immunodeficiency Virus Type 1 (HIV-1) Assay for HIV Load Monitoring in South Africa Compared to the Roche Cobas AmpliPrep-Cobas Amplicor, Roche Cobas AmpliPrep-Cobas TaqMan HIV-1, and BioMerieux NucliSENS EasyQ HIV-1 Assays

Abstract

The implementation of antiretroviral therapy demands the need for increased access to viral load (VL) monitoring. Newer real-time VL testing technologies are faster and have larger dynamic ranges and fully automated extraction to benefit higher throughputs in resource-poor environments. The Abbott RealTime human immunodeficiency virus type 1 (HIV-1) assay was evaluated as a new option for testing for HIV-1 subtype C in South Africa, and its performance was compared to the performance of existing assays (the Cobas AmpliPrep-Cobas TaqMan HIV-1, version 1, assay; the AmpliPrep-Cobas Monitor standard HIV-1 assay; and the NucliSENS EasyQ-EasyMag HIV-1 assay) in a high-throughput laboratory. The total precision of the RealTime HIV-1 assay was acceptable over all viral load ranges. This assay compared most favorably with the Cobas AmpliPrep-Cobas TaqMan HIV-1 assay (R 2 ‫؍‬ 0.904), with a low standard deviation of difference being detected (0.323 copies/ml). The bias against comparator assays ranged from ؊0.001 copies/ml to ؊0.228 copies/ml. Variability in the reporting of VLs for a 20-member subtype panel compared to the variability of other assays was noted with subtypes G and CRF02-AG. The RealTime HIV-1 assay can test 93 samples per day with minimal manual preparation, less staff, and the minimization of contamination through automation. This assay is suitable for HIV-1 subtype C VL quantification in South Africa.

HIV-1 Load Comparison Using Four Commercial Real-Time Assays

“…Our findings confirm the results found by Scott et al (17) that, for a group of predominantly HIV-1 C subtype patients, CAP/ CTM v2.0 presented a positive bias of 0.33 and 0.48 log copies/ml over the m2000 RealTime and CAP/CTM v1.0 assays, respectively. In our study, an improved sensitivity of the 2.0 over the 1.0 version was also observed, in agreement with previous studies (13,17,18); Scott et al also described more quantifiable results down to 20 HIV RNA copies/ml for ARVtreated patients (17, 18); since our samples originated from newly diagnosed and untreated patients, we were unable to confirm this point. In our study, the NucliSens HIV-1 EasyQ v1.2 assay was the least favorable, exhibiting significantly lower viral loads and wider discrepancies.…”

Cross-Platform Analysis of HIV-1 RNA Data Generated by a Multicenter Assay Validation Study with Wide Geographic Representation

“…An understanding of how the results generated from the different HIV-1 RNA assays compare is critical for all HIV-1 subtypes, especially since the genetic diversity of HIV-1 continues to evolve and underquantitation of HIV-1 continues to be documented (4,11,13,23). Surveillance and comparative studies worldwide (2,17,22,25,30,31) are extremely important for documenting potential problems and forcing manufacturers to improve their assays in response to deficiencies (6,7,14). The high cost associated with the full automation of new real-time PCR assays has forced manufacturers to offer manual versions of the assays, but the impact of using manual extraction methods on precision across laboratories is not fully understood (5,19).…”

An International Collaboration To Standardize HIV-2 Viral Load Assays: Results from the 2009 ACHI E V 2E Quality Control Study

“…Indeed, the average genetic diversity between HIV-2 groups A and B is ϳ20% in the gag gene, which is higher than that among HIV-1 group M isolates (13). The problem of HIV-2 genetic diversity for accurate viral load quantification is similar to that previously observed for HIV-1, where genetic diversity makes HIV-1 RNA quantification difficult, especially in patients infected by HIV-1 non-B subtypes (5,10,27,32). All of the assay methods involved a PCR step.…”