Comparative performances of HIV-1 RNA load assays at low viral load levels: Results of an international collaboration

Luke C. Swenson, Bryan Cobb, Anna Maria Geretti, P. Richard Harrigan, Mario Poljak, Carole Seguin-Devaux, Chris Verhofstede, Marc Wirden, Alessandra Amendola, Jurg Boni, Thomas Bourlet, Jon B. Huder, Jean Claude Karasi, Snjezana Zidovec Lepej, Maja M. Lunar, Odette Mukabayire, Rob Schuurman, Janez Tomažič, Kristel Van Laethem, Linos VandekerckhoveAnnemarie M.J. Wensing*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

42 Citations (Scopus)


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 ∼ 100 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.

Original languageEnglish
Pages (from-to)517-523
Number of pages7
JournalJournal of Clinical Microbiology
Issue number2
Publication statusPublished - Feb 2014


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