OBJECTIVE: To investigate the application of the new COBAS Ampliprep Taqman HIV-1 assay in comparison with the COBAS HIV-1 Ampliprep AMPLICOR MONITOR ultrasensitive assay version 1.5, with a particular focus on the most clinically relevant region near the lower limit of quantification. METHODS: Scatterplots and the Bland-Altman plot were used to inspect the degree of agreement between the 2 assays when tested on samples from the British Columbia Centre for Excellence in HIV/AIDS monitoring and evaluation system. Consistency of clinically applicable values at low HIV-1 RNA copy number was assessed from samples from individuals with previously undetectable Amplicor results. RESULTS: Despite general agreement of these assays over a wide dynamic range, the Taqman assay resulted in a nearly 2-fold increase (from 3.6% to 6.9%) in the number of patients experiencing a plasma HIV-1 RNA level >50 copies per milliliter after being suppressed to levels <50 copies per milliliter consistently during the previous year (P < 0.01). In addition, rare discrepancies between the 2 assays were observed to be as high as 0.7 log10 copies per milliliter. The kappa statistic was 0.19, indicating only slight agreement at the critical threshold of 50 HIV RNA copies per milliliter, with 43% of undetectable samples in the Amplicor assay testing detectable in the Taqman assay (median 70 copies/mL; interquartile range 60-83 copies/mL). CONCLUSIONS: The increased frequency of detectable plasma HIV-1 RNA levels at the threshold of 50 copies per milliliter with the new Taqman assay has important implications for highly active antiretroviral therapy monitoring. Until there is clinical evidence that patients with detectable HIV by the Taqman assay (but undetectable HIV with Amplicor) have differential outcomes, it is unclear whether the Taqman assay is appropriate for routine management of HIV-1 therapy, and caution is required in the interpretation of low-level viremia by the Taqman assay until a clinical validation of a new cutoff is performed.
OBJECTIVE: To investigate the application of the new COBAS Ampliprep Taqman HIV-1 assay in comparison with the COBAS HIV-1 Ampliprep AMPLICOR MONITOR ultrasensitive assay version 1.5, with a particular focus on the most clinically relevant region near the lower limit of quantification. METHODS: Scatterplots and the Bland-Altman plot were used to inspect the degree of agreement between the 2 assays when tested on samples from the British Columbia Centre for Excellence in HIV/AIDS monitoring and evaluation system. Consistency of clinically applicable values at low HIV-1 RNA copy number was assessed from samples from individuals with previously undetectable Amplicor results. RESULTS: Despite general agreement of these assays over a wide dynamic range, the Taqman assay resulted in a nearly 2-fold increase (from 3.6% to 6.9%) in the number of patients experiencing a plasma HIV-1 RNA level >50 copies per milliliter after being suppressed to levels <50 copies per milliliter consistently during the previous year (P < 0.01). In addition, rare discrepancies between the 2 assays were observed to be as high as 0.7 log10 copies per milliliter. The kappa statistic was 0.19, indicating only slight agreement at the critical threshold of 50 HIV RNA copies per milliliter, with 43% of undetectable samples in the Amplicor assay testing detectable in the Taqman assay (median 70 copies/mL; interquartile range 60-83 copies/mL). CONCLUSIONS: The increased frequency of detectable plasma HIV-1 RNA levels at the threshold of 50 copies per milliliter with the new Taqman assay has important implications for highly active antiretroviral therapy monitoring. Until there is clinical evidence that patients with detectable HIV by the Taqman assay (but undetectable HIV with Amplicor) have differential outcomes, it is unclear whether the Taqman assay is appropriate for routine management of HIV-1 therapy, and caution is required in the interpretation of low-level viremia by the Taqman assay until a clinical validation of a new cutoff is performed.
Authors: Luke C Swenson; Jeong Eun Min; Conan K Woods; Eric Cai; Jonathan Z Li; Julio S G Montaner; P Richard Harrigan; Alejandro Gonzalez-Serna Journal: AIDS Date: 2014-05-15 Impact factor: 4.177
Authors: Christina M Lalama; Cheryl Jennings; Victoria A Johnson; Robert W Coombs; John E McKinnon; James W Bremer; Bryan R Cobb; Gavin A Cloherty; John W Mellors; Heather J Ribaudo Journal: J Clin Microbiol Date: 2015-06-10 Impact factor: 5.948
Authors: Luke C Swenson; Bryan Cobb; Anna Maria Geretti; P Richard Harrigan; Mario Poljak; Carole Seguin-Devaux; Chris Verhofstede; Marc Wirden; Alessandra Amendola; Jurg Boni; Thomas Bourlet; Jon B Huder; Jean-Claude Karasi; Snjezana Zidovec Lepej; Maja M Lunar; Odette Mukabayire; Rob Schuurman; Janez Tomazic; Kristel Van Laethem; Linos Vandekerckhove; Annemarie M J Wensing Journal: J Clin Microbiol Date: 2013-12-04 Impact factor: 5.948
Authors: J Troy Grennan; Mona R Loutfy; DeSheng Su; P Richard Harrigan; Curtis Cooper; Marina Klein; Nima Machouf; Julio S G Montaner; Sean Rourke; Christos Tsoukas; Bob Hogg; Janet Raboud Journal: J Infect Dis Date: 2012-04-15 Impact factor: 5.226
Authors: James H Willig; Christa R Nevin; James L Raper; Michael S Saag; Michael J Mugavero; Amanda L Willig; Jeffrey H Burkhardt; Joseph E Schumacher; Victoria A Johnson Journal: J Acquir Immune Defic Syndr Date: 2010-08 Impact factor: 3.731
Authors: Janet M Raboud; Mona R Loutfy; DeSheng Su; Ahmed M Bayoumi; Marina B Klein; Curtis Cooper; Nima Machouf; Sean Rourke; Sharon Walmsley; Anita Rachlis; P Richard Harrigan; Marek Smieja; Christos Tsoukas; Julio S G Montaner; Robert S Hogg Journal: BMC Infect Dis Date: 2010-02-25 Impact factor: 3.090
Authors: Christoph Stephan; Valentin Bartha; Eva Herrmann; Nils von Hentig; Pavel Khaykin; Gaby Knecht; Peter Gute; Hans-Reinhard Brodt; Martin Stürmer; Annemarie Berger; Markus Bickel Journal: Med Microbiol Immunol Date: 2012-09-15 Impact factor: 3.402