Comparison of the Bayer VERSANT HCV RNA 3.0 and the Roche COBAS Amplicor HCV Monitor, Version 2.0, assays in HCV genotype 4 infection

Authors

  • W. Jessner,

    1. Department of Internal Medicine IV, Gastroenterology and Hepatology, Vienna Medical University, Vienna
    2. Department of Internal Medicine, Gastroenterology and Hepatology, Innsbruck Medical University, Innsbruck
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    • *

      Patient management and sample testing were performed at Vienna Medical University and Krankenanstalt Rudolfstiftung, data analysis and writing of the manuscript were performed at Innsbruck Medical University, which is the present address of the first author.

  • T. Watkins-Riedel,

    1. Department of Clinical Virology, Vienna Medical University, Vienna
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    • Present address: Department of Hygiene, Wilhelminenspital, Austria.

  • C. Müller,

    1. Department of Internal Medicine IV, Gastroenterology and Hepatology, Vienna Medical University, Vienna
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  • E. Formann,

    1. Department of Internal Medicine IV, Gastroenterology and Hepatology, Vienna Medical University, Vienna
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    • Present address: Department of Internal Medicine IV, Wilhelminenspital, Austria.

  • M. Gschwantler,

    1. Department of Internal Medicine IV, Krankenanstalt Rudolfstiftung, Vienna, Austria
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    • Present address: Department of Internal Medicine IV, Wilhelminenspital, Austria.

  • P. Ferenci

    1. Department of Internal Medicine IV, Gastroenterology and Hepatology, Vienna Medical University, Vienna
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Peter Ferenci, MD, Professor of Medicine, Department of Internal Medicine, Gastroenterology and Hepatology, University of Vienna, Allgemeines Krankenhaus, Waehringer Guertel 18–20, A-1090 Vienna, Austria. E-mail: peter.ferenci@meduniwien.ac.at

Abstract

summary Prediction of treatment response is clinically important in chronic hepatitis C virus (HCV) genotype 4 infection. Early viral kinetics is useful in this respect for genotype 1 but interpretation is dependent on assay linearity and reproducibility. The VERSANT HCV RNA 3.0 (bDNA-3.0) and the COBAS Amplicor HCV Monitor 2.0 (HCM-2.0) have been widely used quantitative assays. We wanted to comparatively evaluate the two tests in a large genotype 4 sample. Genotyping was performed by NS5b sequencing. Viral load was tested in parallel in 32 patients at least six times on antiviral therapy with interferon α (IFNα). Totally, 198 samples within a quantitative range from undetectable to about 7 × 106 IU/mL (bDNA-3.0) were obtained and compared. Twenty-two samples with viral load above 500 000 IU/mL tested by HCM-2.0 were 1:100 diluted and retested. Quantitative values were fitted to a third order polynomial (M = 0.118303 + 1.07503 × V+ 0.0112128 × V2 − 0.0055504 × V3; M…HCM-2.0, V…bDNA-3.0, both log IU/mL) showing progressive nonlinearity of HCM-2.0 above 100 000 IU/mL but better clinical sensitivity with respect to bDNA-3.0. Dilution lead to a gain of at least a factor of 2.7 and thus, overestimation compared with bDNA-3.0. Deviation from linearity and overestimation upon dilution by HCM-2.0 are similar with HCV genotype 4, compared with other HCV genotypes. Differences in test performance were not detected for subtypes but for individual patients possibly related to specific quasispecies patterns. The interpretation of viral kinetic data becomes difficult due to overestimation upon dilution of baseline values by HCM-2.0.

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