Use of an HIV-1 reverse-transcriptase enzyme-activity assay to measure HIV-1 viral load as a potential alternative to nucleic acid-based assay for monitoring antiretroviral therapy in resource-limited settings

H. Syed Iqbal, P. Balakrishnan, Anitha J. Cecelia, Suniti Solomon, N. Kumarasamy, Vidya Madhavan, K. G. Murugavel, Aylur K. Ganesh, Sunil Suhas Solomon, Kenneth H. Mayer, Suzanne M. Crowe

Research output: Contribution to journalArticlepeer-review

Abstract

An inexpensive and technically less-demanding methodology to quantify HIV-1 viral load would be of great value for resource-limited settings, where the nucleic-acid amplification technique (NAAT) is impractical and/or resource-prohibitive. In this study, an HIV-1 reverse-transcriptase enzyme-activity assay (ExaVir Load assay, version 1) was compared with the gold standard RT-PCR assay, Roche HIV-1 Amplicor Monitor, version 1.5. A total of 121 plasma specimens were used for the evaluation. ExaVir Load had a sensitivity of 97 % and a specificity of 71 % in identifying specimens with <400 copies ml-1 in the Roche RT-PCR assay as being less than the detection limit of the assay (5500 copies ml-1). The mean difference (95% limits of agreement) between Roche RT-PCR and ExaVir Load was -0.23 (-1.59 to 1.13) log10(copies ml-1) by Bland-Altman analysis. Significant negative correlations were seen between CD4+ T-cell counts and the ExaVir Load assay (r=-0.32, P<0.05), and between CD4+ T-cell counts and the Roche RT-PCR (r=-0.38, P<0.01). The present study with HIV-1 showed a strong correlation between the ExaVir Load assay and the RT-PCR assay. Hence, the ExaVir Load assay could be considered for use in resource-limited settings as an alternative viral-load assay to the standard NAAT-based assay after further evaluation with prospective specimens.

Original languageEnglish (US)
Pages (from-to)1611-1614
Number of pages4
JournalJournal of medical microbiology
Volume56
Issue number12
DOIs
StatePublished - Dec 2007
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)

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