HIV1 RNA Quantitation

HIV-1 RNA quantitation by bDNA signal amplification with the VERSANT HIV-1 RNA 3.0 assay was assessed in a large multicenter trial preceding U.S. product registration. In this evaluation, the test showed a specificity of 97.6% and a clinical sensitivity between 98.7% and 65.3%, depending on the HIV-1-infected patient's CD4+ T-cell counts. As detection limit, 75 HIV-1 RNA copies/ mL were established and the assay was linear up to 500,000 HIV-1 RNA copies/mL. Mean intra- and overall interassays imprecisions were 18.1% and 21.3%, respec-tively.[16] The test could quantify HIV-1 group M subtypes, but must not be used for detecting other subtypes of HIV-1 or HIV-2 strains.[17]

Commercial assays for quantitation of HIV-1 RNA in clinical samples lack standardization and so far have not been universally calibrated against the appropriate WHO reference preparation, which was available since 2001.[18] Consequently, quantitative values obtained with the third-generation bDNA assay were, on an average, 39% lower than the measurements recorded with the PCR-based Roche Cobas Amplicor HIV-1 Monitor (version 1.5) and the differences were consistent across the whole common reportable range of the two tests.[16] Despite these striking discrepancies, the treatment guidelines of the Department of Health and Human Services for HIV-infected adults and adolescents state that an HIV-1 RNA concentration of 55,000 copies/mL, as determined by either RT-PCR or bDNA, might represent a useful laboratory marker for the decision whether an asymptomatic patient with a CD4+ T-cell count of greater than 350/mm3 should be treated with antiretroviral agents or instead deferred from therapy.[19]

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

Get My Free Ebook


Post a comment