Assessment of the low-cost Cavidi ExaVir Load assay for monitoring HIV viral load in pediatric and adult patients.
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.
Greengrass
Vicki
V
Clinical Research Laboratory, Centre for Virology, Burnet Institute, Melbourne, Australia.
Lohman
Barbera
B
Morris
Lisa
L
Plate
Megan
M
Steele
Pauline M
PM
Walson
Judd L
JL
Crowe
Suzanne M
SM
D000328:Adult; D002648:Child; D015658:HIV Infections / Q000097:blood / Q000821:virology*; D054303:HIV Reverse Transcriptase / Q000097:blood*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000191:economics / Q000379:methods; D012680:Sensitivity and Specificity; D019562:Viral Load / Q000379:methods*
D054303:HIV Reverse Transcriptase