Send to

Choose Destination
J Clin Microbiol. 2014 Feb;52(2):517-23. doi: 10.1128/JCM.02461-13. Epub 2013 Dec 4.

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

Author information

BC Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada.


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.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center