Standardization and performance evaluation of “modified” and “ultrasensitive” versions of the Abbott RealTime HIV-1 assay, adapted to quantify minimal residual viremia

Amendola, Alessandra; Bloisi, Maria; Marsella, Patrizia; Sabatini, Rosella; Bibbò, Angela; Angeletti, Claudio; Capobianchi, Maria Rosaria

doi:10.1016/j.jcv.2011.04.012

Cited by 18 publications

(15 citation statements)

References 34 publications

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“…Furthermore, the assays themselves have inherently lower precision, reproducibility, and sensitivity at the lower ends of their dynamic ranges, which likely contributes to interassay disagreement at low viral loads. Assays exist to quantify viral loads even to single-copy levels, and commercial assays can be modified to accommodate low viral loads (43)(44)(45)(46). However, these often require large volumes of blood plasma, up to 30 ml in some cases (43), and this precludes their routine use in the clinic setting.…”

Section: Discussionmentioning

confidence: 99%

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

et al. 2014

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Low-level viremia during antiretroviral therapy and its accurate measurement are increasingly relevant. Here, we present an international collaboration of 4,221 paired blood plasma viral load (pVL) results from four commercial assays, emphasizing the data with low pVL. The assays compared were the Abbott RealTime assay, the Roche Amplicor assay, and the Roche TaqMan version 1 and version 2 assays. The correlation between the assays was 0.90 to 0.97. However, at a low pVL, the correlation fell to 0.45 to 0.85. The observed interassay concordance was higher when detectability was defined as 200 copies/ml than when it was defined as 50 copies/ml. A pVL of ϳ100 to 125 copies/ml by the TaqMan version 1 and version 2 assays corresponded best to a 50-copies/ml threshold with the Amplicor assay. Correlation and concordance between the viral load assays were lower at a low pVL. Clear guidelines are needed on the clinical significance of low-level viremia.

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Section: Discussionmentioning

confidence: 99%

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

et al. 2014

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“…The stated linear quantification range of the standard version is 40 to 10,000,000 copies/ml (0.6-ml protocol), and the reported LOD is 40 copies/ml. For samples with HIV-1 RNA levels of Ͻ40 copies/ ml, a modified protocol of Abbott assay, with an LOD of 19 copies/ml, was used (22). The modified protocol of the Abbott assay was obtained by introducing some changes to the standard protocol, namely, using a new calibration curve to cover low HIV-1 RNA concentrations (10 to 1,000 copies/ml), reducing the volume of the internal control, and adopting open-mode software for quantification.…”

Section: Methodsmentioning

confidence: 99%

“…The modified protocol of the Abbott assay was obtained by introducing some changes to the standard protocol, namely, using a new calibration curve to cover low HIV-1 RNA concentrations (10 to 1,000 copies/ml), reducing the volume of the internal control, and adopting open-mode software for quantification. The performance characteristics of the modified version were previously described, showing high accuracy and precision (22).…”

Section: Methodsmentioning

confidence: 99%

“…In this case, the comparison was performed using the modified protocol of the Abbott assay (reported LOD, 19 copies/ml) (22), in order to use assays with presumed comparable sensitivities. We first reassessed the actual analytical sensitivity of each of the two assays (i.e., the minimal concentration of HIV-1 RNA detected with response probability of 95%, or the LOD), using 7 replicates of each 2-fold dilution (from 128 to 1 copies/ml) of the HIV-WR1.…”

Section: Assay Comparison On Clinical Samplesmentioning

confidence: 99%

“…In addition, the HIV-1 RNA working reagent 1 for NAT assays (HIV-WR1), diluted from 1,053 to 1 copies/ml, was evaluated with both assays. For VL concentrations of Ͻ40 copies/ml, the comparison was conducted in two ways: (i) considering HIV-1 RNA values from 20 to 40 copies/ml with Roche as "detected Ͻ40 copies/ml," in order to align them with the Abbott assay results, and (ii) using the modified protocol of the Abbott assay (limit of detection [LOD], 19 copies/ml) (22) in order to compare data for VL of Ͻ40 copies/ml with the Roche assay.…”

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Ability of Two Commercially Available Assays (Abbott RealTi m e HIV-1 and Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 Version 2.0) To Quantify Low HIV-1 RNA Levels (<1,000 Copies/Milliliter): Comparison with Clinical Samples and NIBSC Working Reagent for Nucleic Acid Testing Assays

et al. 2014

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Concordance between molecular assays may be suboptimal at low HIV-1 viremia levels (<1,000 copies/ml); therefore, it may be difficult to define and compare virologic endpoints for successful and failed therapy. We compared two commercial assays (the Abbott RealTime HIV-1 and the Roche Cobas AmpliPrep/TaqMan HIV-1 version 2.0) for their ability to detect and quantify low viral loads. A comparison was performed using 167 residual clinical samples (with values ranging from "not detected" to 1,000 copies/ml, as measured by the Abbott assay) and the National Institute and Biological Standards and Control (NIBSC) HIV-1 RNA working reagent 1 for nucleic acid amplification techniques (NAT) assays (serially diluted to a range from 1 to 1,000 copies/ ml). Quantitative results were compared using Lin's concordance correlation coefficient and a Bland-Altman plot. Concordance with the qualitative results was measured by Cohen's kappa statistic. With clinical samples, the degree of interassay concordance of the qualitative results at a 40-copies/ml HIV-1 RNA threshold was substantial ( ‫؍‬ 0.762); the correlation among the quantified samples was suboptimal (concordance correlation coefficient, 0.728; P < 0.0001); the mean difference of the values between the Roche and Abbott assays was 0.193 log 10 copies/ml. Using the HIV-1 RNA working reagent 1 for NAT assays, the results provided by the Roche assay were, on average, 3 times higher than expected, while the Abbott assay showed high accuracy. The Roche assay was highly sensitive, being able to detect a level as low as 3.5 copies/ml HIV-1 RNA with 95% probability. The performance characteristics of each molecular assay should be taken into account when HIV-1 RNA threshold values for "virologic suppression," "virologic failure," "persistent low viral loads," etc., are defined and indicated in the support of clinical decisions.

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Evaluation of the Aptima^® HIV‐1 Quant Dx assay for HIV‐1 RNA viral load detection and quantitation in plasma of HIV‐1‐infected individuals: A comparison with Abbott RealTime HIV‐1 assay

Amendola

Pisciotta

Aleo

et al. 2016

Journal of Medical Virology

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The Hologic Aptima ® HIV‐1 Quant Dx assay (Aptima HIV) is a real‐time transcription‐mediated amplification method CE‐approved for use in diagnosis and monitoring of HIV‐1 infection. The analytical performance of this new assay was compared to the FDA‐approved Abbott RealTi m e HIV‐1 (RealTime). The evaluation was performed using 220 clinical plasma samples, the WHO 3rd HIV‐1 International Standard, and the QCMD HIV‐1 RNA EQA. Concordance on qualitative results, correlation between quantitative results, accuracy, and reproducibility of viral load data were analyzed. The ability to measure HIV‐1 subtypes was assessed on the second WHO International Reference Preparation Panel for HIV‐1 Subtypes. With clinical samples, inter‐assay agreement for qualitative results was high (91.8%) with Cohen's kappa statistic equal to 0.836. For samples with quantitative results in both assays (n = 93), Lin's concordance correlation coefficient was 0.980 ( P < 0.0001) and mean differences of measurement, conducted according to Bland–Altman method, was low (0.115 log 10 copies/ml). The Aptima HIV quantified the WHO 3rd HIV‐1 International Standard diluted from 2000 to 31 cp/ml (5,700–88 IU/ml) at expected values with excellent linearity (R 2 > 0.970) and showed higher sensitivity compared to RealTime being able to detect HIV‐1 RNA in 10 out of 10 replicates containing down to 7 cp/ml (20 IU/ml). Reproducibility was very high, even at low HIV‐1 RNA values. The Aptima HIV was able to detect and accurately quantify all the main HIV‐1 subtypes in both reference panels and clinical samples. Besides excellent performance, Aptima HIV shows full automation, ease of use, and improved workflow compared to RealTime. J. Med. Virol. 88:1535–1544, 2016 . © 2016 Wiley Periodicals, Inc.

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Standardization and performance evaluation of “modified” and “ultrasensitive” versions of the Abbott RealTime HIV-1 assay, adapted to quantify minimal residual viremia

Cited by 18 publications

References 34 publications

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

Ability of Two Commercially Available Assays (Abbott RealTi m e HIV-1 and Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 Version 2.0) To Quantify Low HIV-1 RNA Levels (<1,000 Copies/Milliliter): Comparison with Clinical Samples and NIBSC Working Reagent for Nucleic Acid Testing Assays

Evaluation of the Aptima^® HIV‐1 Quant Dx assay for HIV‐1 RNA viral load detection and quantitation in plasma of HIV‐1‐infected individuals: A comparison with Abbott RealTime HIV‐1 assay

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Standardization and performance evaluation of “modified” and “ultrasensitive” versions of the Abbott RealTime HIV-1 assay, adapted to quantify minimal residual viremia

Cited by 18 publications

References 34 publications

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

Ability of Two Commercially Available Assays (Abbott RealTi m e HIV-1 and Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 Version 2.0) To Quantify Low HIV-1 RNA Levels (<1,000 Copies/Milliliter): Comparison with Clinical Samples and NIBSC Working Reagent for Nucleic Acid Testing Assays

Evaluation of the Aptima® HIV‐1 Quant Dx assay for HIV‐1 RNA viral load detection and quantitation in plasma of HIV‐1‐infected individuals: A comparison with Abbott RealTime HIV‐1 assay

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Evaluation of the Aptima^® HIV‐1 Quant Dx assay for HIV‐1 RNA viral load detection and quantitation in plasma of HIV‐1‐infected individuals: A comparison with Abbott RealTime HIV‐1 assay