Publications & Reports

Assessment of the low-cost Cavidi ExaVir Load assay for monitoring HIV viral load in pediatric and adult patients.

Greengrass V, Lohman B, Morris L, Plate M, Steele PM, Walson JL, Crowe SM
Clinical Research Laboratory, Centre for Virology, Burnet Institute, Melbourne, Australia.


BACKGROUND: Viral load (VL) is a critical marker for monitoring HIV disease progression and response to antiretroviral therapy. In resource-constrained settings, there is a need for a simple and inexpensive assay to monitor infected adults and children. METHODS: We compared versions 2 and 3 of the ExaVir Load assay, Cavidi AB (HIV RT) with the Roche, COBAS Amplicor HIV-1 Monitor assay (HIV RNA) for quantifying HIV VL. RESULTS: The HIV RT version 2 assay showed good sensitivity with detection in 94% of samples with HIV RNA >1000 copies per milliliter. Adult samples were tested using HIV RT version 2 (n = 35) and version 3 (n = 23) assays with plasma volumes of 1 mL (recommended), 0.5 mL and 0.25 mL in comparison with HIV RNA. The HIV RT and HIV RNA assay results were comparable when tested using different volumes. Comparison of results from pediatric samples (n = 27), tested using 1 mL and a smaller volume by HIV RT version 2 were not significantly different. CONCLUSIONS: The HIV RT assay was comparable to the HIV RNA assay with sensitivity approaching that of HIV RNA. Smaller volumes than the recommended 1 mL can be used, improving utility of this assay for pediatric monitoring.


  • Journal: Journal of Acquired Immune Deficiency Syndromes
  • Published: 01/11/2009
  • Volume: 52
  • Issue: 3
  • Pagination: 387-390