Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

Abstract

Low-level viremia during antiretroviral therapy and its accurate measurement are increasingly relevant. Here, we present an international collaboration of 4,221 paired blood plasma viral load (pVL) results from four commercial assays, emphasizing the data with low pVL. The assays compared were the Abbott RealTime assay, the Roche Amplicor assay, and the Roche TaqMan version 1 and version 2 assays. The correlation between the assays was 0.90 to 0.97. However, at a low pVL, the correlation fell to 0.45 to 0.85. The observed interassay concordance was higher when detectability was defined as 200 copies/ml than when it was defined as 50 copies/ml. A pVL of ϳ100 to 125 copies/ml by the TaqMan version 1 and version 2 assays corresponded best to a 50-copies/ml threshold with the Amplicor assay. Correlation and concordance between the viral load assays were lower at a low pVL. Clear guidelines are needed on the clinical significance of low-level viremia.

Ability of Two Commercially Available Assays (Abbott RealTi m e HIV-1 and Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 Version 2.0) To Quantify Low HIV-1 RNA Levels (<1,000 Copies/Milliliter): Comparison with Clinical Samples and NIBSC Working Reagent for Nucleic Acid Testing Assays

“…Overall, our results on the performance characteristics of these two assays at LVL are aligned with similar data previously reported with clinical samples (20,(29)(30)(31) and with the 2nd international HIV-1 RNA WHO standard (19). In particular, although there is good agreement between the commonly used diagnostic assays for detecting both HIV-1 B and non-B subtypes along the common range of detection (14,15,18,(32)(33)(34), the interassay correlation is lower at the lower limit of quantification (16-18, 21, 30, 31, 35).…”

Point-of-Care Cepheid Xpert HIV-1 Viral Load Test in Rural African Communities Is Feasible and Reliable

“…It is important to note that underestimation of HIV-1 RNA at low levels with the Abbott m2000rt assay was reported previously (29,32). For example, while the overall correlation between the Abbott RealTime assay and the Roche Amplicor assay was 0.90, it was only 0.45 at a low level of HIV-1 RNA (32).…”

Aptima HIV-1 Quant Dx—A fully automated assay for both diagnosis and quantification of HIV-1

“…Assays that quantify the various HIV subtypes and recombinants with equal efficiency and accuracy are required for effective clinical management of patients on ART [35,36,37,38]. Good agreement of VL results were seen in a method comparison between Aptima and CAP/CTM (Fig.…”