A comparison of serum HIV-1 RNA levels as measured by two quantitative assays in zidovudine-treated, asymptomatic, HIV-infected individuals
Weverling, G.J.; Lange, J.M.; de Jong, M.D.; de Weerd, H.; Goudsmit, J.; de Wolf, F.
Antiviral Therapy 1(4): 255-263
1996
ISSN/ISBN: 1359-6535 PMID: 11324828 Document Number: 463982
HIV-1 RNA levels were measured in stored serum samples from 24 Dutch zidovudine-treated participants of a zidovudine efficacy study (European-Australian Collaborative Group Study 017) at weeks -3, 0, 4 and 8, using quantitative nucleic acid sequence-based amplification (NASBA; Organon Technika) and quantitative reverse transcriptase-polymerase chain reaction (Amplicor; Roche Molecular Systems). Before treatment, HIV-1 RNA levels as measured by NASBA were 0.49 logs higher than the levels measured by the Amplicor assay (95% confidence interval (CI) 0.32-0.66). During treatment, this difference decreased significantly to 0.27 logs (95% CI 0.01-0.53; difference 0.22 logs; 95% CI 0.05-0.37). The smaller difference between the results of the two assays during treatment was a consequence of a larger decline in RNA level as measured by NASBA compared with that measured by the Amplicor assay (mean change after 4 weeks 0.77 and 0.49 logs, respectively). At week 8, the mean HIV-1 RNA level was still significantly below baseline values as measured by NASBA, but not when measured by the Amplicor assay. Discrepancies in individual responses as measured by the two assays were also observed. These differences should be considered in interpreting analyses of clinical trials and relationships between HIV-1 RNA level and clinical outcome, as well as in the use of RNA level in the management of HIV-infected patients.