Clinical evaluation of the automated COBAS AMPLICOR HCV MONITOR test version 2.0 for quantifying serum hepatitis C virus RNA and comparison to the quantiplex HCV version 2.0 test

A second-generation hepatitis C virus (HCV) quantitative assay (COBAS AMPLICOR HCV MONITOR Test, version 2.0; COBAS HCM-2) has been developed, with the intention of achieving equivalent quantification of all HCV genotypes and improving assay performance. To evaluate the clinical performance of COBAS HCM-2 and its utility in predicting the response to alpha interferon treatment, sera from 215 chronic hepatitis C patients were analyzed and the results were compared with those obtained by the Quantiplex bDNA HCV RNA, version 2.0, assay (bDNA-2). The COBAS HCM-2 had significantly greater sensitivity than bDNA-2 (94.9 versus 88.4%; P < 0.001) when performed with sera from chronic hepatitis C patients who were viremic by a qualitative PCR test. The standard deviations for the within-run and between-run reproducibilities of COBAS HCM-2 were <0. 1 and <0.2, respectively, and it showed an improved linear range between genotypes with the threefold serial dilutions tested (r(2) = 0.986 to 0.995). The COBAS HCM-2 results were positively correlated with the bDNA-2 results, but the values for COBAS HCM-2 were on average 0.96 log lower than the values for bDNA-2. The mean difference in quantification values between these two assays did not differ among samples with different genotypes (0.70 to 1.00 log). No genotype-dependent difference in viral load was observed. The pretreatment viral load was significantly lower in complete responders. By using multivariate analysis, the viral load 2 weeks after the initiation of alpha interferon treatment was the strongest predictor of a complete response. In conclusion, COBAS HCM-2 demonstrated good sensitivity, linearity, and reproducibility and efficiency equal to that of bDNA-2 for the quantification of HCV genotypes 1 and 2. Hence, this assay provides a rapid and reliable method for the quantification of HCV RNA in serum and is useful for the planning of interferon treatment.     

Comparative evaluation of the VERSANT HCV RNA 3.0, QUANTIPLEX HCV RNA 2.0, and COBAS AMPLICOR HCV MONITOR version 2.0 Assays for quantification of hepatitis C virus RNA in serum

A comparison of quantitative results expressed in hepatitis C virus (HCV) international units per milliliter, obtained from the VERSANT HCV RNA 3.0 (bDNA-3.0) assay, the QUANTIPLEX HCV RNA 2.0 (bDNA-2.0) assay, and the COBAS AMPLICOR HCV MONITOR version 2.0 (HCM-2.0) test was performed. A total of 168 patient specimens submitted to the Mayo Clinic Molecular Microbiology Laboratory for HCV quantification or HCV genotyping were studied. Of the specimens tested, 97, 88, and 79% yielded quantitative results within the dynamic range of the bDNA-3.0, bDNA-2.0, and HCM-2.0 assays, respectively. Overall, there was substantial agreement between the results generated by all three assays. A total of 15 out of 29 (52%) of the specimens determined to contain viral loads of <31,746 IU/ml by the bDNA-3.0 assay were categorized as containing viral loads within the range of 31,746 to 500,000 IU/ml by the bDNA-2.0 assay. Although substantial agreement was noted between the results generated by the bDNA-2.0 and bDNA-3.0 assays, a bias toward higher viral titer by the bDNA-2.0 assay was noted (P = 0.001). Likewise, although substantial agreement was noted between the results generated by the HCM-2.0 and bDNA-3.0 assays, a bias toward higher viral titer by the bDNA-3.0 assay was noted (P < or = 0.001). The discrepancy between the HCM-2.0 and bDNA-3.0 results was more pronounced when viral loads were >500,000 IU/ml and resulted in statistically significant differences (P < or = 0.001) in determining whether viral loads were above or below 800,000 IU/ml of HCV RNA, the proposed threshold value for tailoring the duration of combination therapy. The expression of quantitative values in HCV international units per milliliter was a strength of both the bDNA-3.0 and HCM-2.0 assays.     

Evaluation of an automated, highly sensitive, real-time PCR-based assay (COBAS Amplipreptrade mark/COBAS TaqMantrade mark) for quantification of HCV RNA

BACKGROUND: Diagnosis of hepatitis C virus (HCV) infection and its therapy is based on qualitative and quantitative measurement of HCV RNA. OBJECTIVES: A new assay that employs automated specimen extraction and real-time RT-PCR (COBAS Amplipreptrade mark/COBAS TaqMantrade mark, "CAP/CTM", Roche Diagnostics, Pleasanton, USA) was designed for linear quantification and highly sensitive detection of HCV RNA. STUDY DESIGN: The performance characteristics of CAP/CTM were compared to standard RT-PCR-based COBAS Amplicor Monitor 2.0 (CAM) assay in a multicenter study. RESULTS: The limit of detection of CAP/CTM was 7.4IU/ml (95% CI 6.2-10.6) and clinical specificity was 99%. The linear range of HCV RNA quantification by CAP/CTM was between 28 and 1.4x10(7)IU/ml, with a correlation coefficient between expected and observed results of >0.99. A fivefold dilution of serum- or plasma-samples showed a linear correlation of HCV RNA levels in undiluted and diluted samples. Analyses of the mean intra- and inter-assay imprecision within the linear range of quantification showed a coefficient of variation of 3% and 3%, respectively. HCV genotypes 1a/b, 2b, 3a, 4, 5 and 6 were equally quantified by the CAP/CTM and CAM assay with mean deviations ranging from -0.29log(10) to 0.32log(10)IU/ml. HCV RNA quantification by CAP/CTM and CAM was highly concordant (correlation coefficient of 0.96). CONCLUSIONS: The CAP/CTM assay is a reliable and robust assay for highly sensitive detection and quantification of HCV RNA within a broad linear range.     

Verification of an assay for quantification of hepatitis C virus RNA by use of an analyte-specific reagent and two different extraction methods

Protocols were designed for quantification and detection of hepatitis C virus (HCV) RNA by the use of an analyte-specific reagent (ASR) (Roche COBAS TaqMan48 [CTM48] HCV) after manual and automated RNA extraction. The purposes were to determine (i) assay performance characteristics using manual and automated RNA extraction methods, (ii) whether measurable range and limit of detection (LOD) of the ASR assay were influenced by genotype, and (iii) correlation of quantification by CTM48 HCV ASR and COBAS Monitor HCV v. 2.0. For HCV genotype 1 (Gt1), the lower limits of quantification after manual extraction were slightly lower than those for automated extraction (1.0 versus 1.5 log(10) IU/ml). Results were linear up to the highest concentration tested after extraction by both methods (manual, 6.1 log(10); automated, 6.4 log(10)). Similar results were obtained for Gt2 (1.8 to 6.8 log(10) IU/ml) and Gt3 (1.6 to 6.8 log(10) IU/ml) after automated extraction. The LOD of Gt1 virus was 10 IU/ml after manual extraction and between 25 and 37.5 IU/ml after automated extraction. Results with Gt2 and Gt3 viruses were similar after automated extraction (Gt2, between 25 and 50 IU/ml; Gt3, 25 IU/ml). Variability (intrarun and interrun, at concentrations throughout the range of quantification) was 相似文献   

Prediction of the efficacy of antiviral therapy for hepatitis C virus infection by an ultrasensitive RT-PCR assay

The efficacy of interferon therapy for hepatitis C virus (HCV) infection improved remarkably. However, virologic relapse occurs in a substantial proportion of patients with virologic response (defined as an HCV RNA level below 50 IU/ml at the end-of-treatment). A highly sensitive RT-nested PCR assay capable of detecting almost a single copy of HCV RNA and a real-time RT-PCR assay to quantify HCV RNA down to 120 copies per ml were developed. The RT-nested PCR assay showed that 1 IU of HCV RNA is equivalent to 12.2 copies. For 28 patients with virologic response (12 relapsers and 16 sustained virologic responders), week-4 and end-of-treatment plasma samples were retested. At week 4, HCV RNA was detected by the RT-nested PCR and qualitative COBAS Amplicor HCV version 2.0 in 8/9 (89%) and 6/9 (67%) samples from relapsers, and in 4/16 (25%) and 2/16 (13%) samples from sustained virologic responders, respectively. End-of-treatment samples with HCV-negative by the qualitative COBAS Amplicor were positive by the present assay in 4/12 (25%) of relapsing patients and 0/16 (0%) of sustained virologic responders. The viral levels detected by the present assay in the Amplicor-negative samples were 3.5-17.3 copies/ml, which is below the detection limit of COBAS Amplicor. In conclusion, the highly sensitive RT-nested PCR assay can predict sustained virologic response at week 4 and virologic relapse at the end-of-treatment more accurately than COBAS Amplicor, suggesting its usefulness in monitoring antiviral therapy for HCV infection.     

Evaluation of the COBAS TaqMan HCV test with automated sample processing using the MagNA pure LC instrument

The COBAS TaqMan HCV Test (TaqMan HCV; Roche Molecular Systems Inc., Branchburg, N.J.) for hepatitis C virus (HCV) performed on the COBAS TaqMan 48 Analyzer (Roche Molecular Systems) currently relies on a manual sample processing method. Implementation of an automated sample processing method would facilitate the clinical use of this test. In this study, we evaluated the performance characteristics of TaqMan HCV following automated sample processing by the MagNA Pure LC instrument (MP; Roche Applied Science, Indianapolis, Ind.). The analytical sensitivity of TaqMan HCV following sample processing by MP was 8.1 IU/ml (95% confidence interval, 6.1 to 15.2). The assay showed good linearity (R(2) = 0.99) across a wide range of HCV RNA levels (25 to 5 x 10(6) IU/ml), with coefficients of variation ranging from 10% to 46%. Among 83 clinical specimens, the sensitivity and specificity of TaqMan HCV were 100% and 95%, respectively, when compared to the COBAS AMPLICOR hepatitis C virus test, version 2.0 (COBAS AMPLICOR; Roche Molecular Systems), with TaqMan HCV detecting two more HCV RNA-positive specimens than COBAS AMPLICOR. Both specimens were confirmed to be HCV RNA positive by the VERSANT HCV RNA qualitative test (Bayer HealthCare LLC, Tarrytown, N.Y.). There was also strong correlation (R(2) = 0.95) and good agreement between the results from TaqMan HCV and the VERSANT HCV RNA 3.0 assay (bDNA) (Bayer HealthCare LLC) among a group of 93 clinical specimens. The MP is a versatile, labor-saving sample processing platform suitable for reliable performance of TaqMan HCV.     

Comparison of serum hepatitis C virus RNA and core antigen concentrations and determination of whether levels are associated with liver histology or affected by specimen storage time

An enzyme immunoassay has recently been developed for the hepatitis C virus (HCV) core antigen. To evaluate the possible association between core antigen and HCV RNA levels with regards to the change in liver histology over time as well as study the effect of duration of storage on viral load results, sequential sera were analyzed from 45 patients with chronic HCV infection who had undergone two or more liver biopsies. A relatively strong association was found between the core antigen and HCV RNA concentrations (r(s) = 0.8), with a core antigen level of 1 pg/ml corresponding to approximately 1,000 IU/ml. All 42 sera with detectable HCV RNA at the time of the second biopsy had core antigen concentrations above 1 pg/ml, and the three sera without detectable HCV RNA had concentrations below 1 pg/ml. No association was found between HCV RNA or core antigen levels and the stage of fibrosis in biopsy samples, progression of fibrosis, necro-inflammatory grade, steatosis, genotype, alanine aminotransferase level, or alcohol consumption. A significant association was demonstrated between the storage time of the samples and both the HCV RNA and core antigen concentrations. The median log HCV RNA concentrations (international units/milliliter) were 3.92 for the sera obtained at the time of the first biopsy (median storage time, 13.0 years) and 4.41 for the sera obtained at the time of the second biopsy (median storage time, 6.6 years) compared to 5.96, the median for 102 different routine clinical patient samples.     

Evaluation of the MagNA pure LC instrument for extraction of hepatitis C virus RNA for the COBAS AMPLICOR Hepatitis C Virus Test,version 2.0

The COBAS AMPLICOR system has played a major role in the transition of molecular diagnostics from research to routine clinical laboratory use by automating the nucleic acid amplification and detection processes. However, sample preparation remains a labor-intensive portion of the procedure. In this study, we evaluated the performance of the COBAS AMPLICOR Hepatitis C Virus Test, version 2.0 (Roche Molecular Systems, Branchburg, N.J.) following manual hepatitis C virus (HCV) RNA extraction versus automated extraction with the MagNA Pure LC instrument (Roche Applied Science, Indianapolis, Ind.). Parallel replicate testing was performed with standard dilutions of 100, 75, 60, and 0 HCV IU/ml and 153 clinical specimens. An analytical sensitivity of 75 IU/ml was achieved with either the manual or the standard-volume (200 microl) automated extraction methodologies (25 of 26 [96.2%]; 95% confidence interval [95% CI], 80.4 to 99.9), whereas the clinical sensitivity and specificity were both 100% with either extraction method. A large-volume (1 ml) automated extraction method was also evaluated with standard dilutions of 40, 25, 10, and 0 IU/ml and the same 153 clinical specimens. The analytical sensitivity of the COBAS AMPLICOR assay with the large-volume extraction method was 25 HCV IU/ml (26 of 26 [100%]; 95% CI, 86.8 to 100), whereas the clinical sensitivity and specificity were both 100%. The MagNA Pure LC instrument is a versatile, labor-saving platform capable of integration with minimal modification of the existing assay procedure. The increased sensitivity of the COBAS AMPLICOR Hepatitis C Virus Test, version 2.0 performed in conjunction with large-volume HCV RNA extraction may be important in HCV diagnostic testing as new therapeutic strategies evolve.     

Evaluation of the clinical usefulness of COBAS AMPLICOR HCV MONITOR assay (ver2.0): Comparison with AMPLICOR HCV MONITOR assay (ver1.0) and HCV core protein level

The quantitation of serum levels of hepatitis C virus (HCV) RNA in chronic hepatitis C has been regarded as one of the most important indicators for the outcome of interferon (IFN) therapy. The AMPLICOR HCV MONITOR version 1.0 (AMPLICOR v1.0) assay is widely used for the evaluation of the HCV level. A new generation assay called the COBAS AMPLICOR HCV MONITOR version 2.0 (COBAS v2.0) assay, which is semiautomated and modified to amplify all genotypes equally, has been developed. The aim of this study was to evaluate the clinical relevance of the COBAS v2.0 assay in comparison with the AMPLICOR v1.0 assay and HCV core protein assay in patients with chronic hepatitis C before IFN therapy. HCV RNA was detectable in 230 cases (97.5%) and undetectable in 6 cases (2.5%) by the COBAS v2.0 assay. The RNA levels measured by the AMPLICOR v1.0 assay correlated significantly with those measured by the COBAS v2.0 assay, and the sensitivity of the new version 2.0 assay was better than that of version 1.0, especially in serotype 2. In relation to the outcome of IFN therapy, HCV RNA levels from virologically sustained responders by the AMPLICOR v1.0 assay were 82.3 +/- 22.9 kcopies/ml in serotype 1 and 36.9 +/- 13.4 kcopies/ml in serotype 2, and those from virologically nonsustained responders were 525.2 +/- 48.6 kcopies/ml in serotype 1 and 76.7 +/- 19.5 kcopies/ml in serotype 2.The rates of sustained response to <100 kcopies/ml were 34/63 (54.0%) in serotype 1 and 24/48 (50.0%) in serotype 2. A statistically significant virological response was seen in serotype 1 (P < 0.0001), but not in serotype 2. In contrast, the levels in virologically sustained responders by the COBAS v2.0 assay were 88.2 +/- 20.5 KIU/ml in serotype 1 and 136.8 +/- 40.1 KIU/ml in serotype 2, and those in virologically nonsustained responders were 608.8 +/- 48.4 KIU/ml in serotype 1 and 328.3 +/- 62.8 KIU/ml in serotype 2. The rates of sustained response to <100 KIU/ml were 33/60 (55.0%) in serotype 1 and 21/35 (60.0%) in serotype 2. Statistical significance in virological response was seen in both serotype 1 (P < 0.0001) and serotype 2 (P < 0.05). Although the sensitivity of the HCV core protein assay was lower than that with the COBAS v2.0 assay, the HCV core protein levels also correlated well with the results of the COBAS v2.0 assay. The HCV core protein levels of virologically sustained responders were 37.6 +/- 12.0 pg/ml in serotype 1, 81.3 +/- 37.0 pg/ml in serotype 2, and those of virologically nonsustained responders were 289.9 +/- 23.5 pg/ml in serotype 1, 191.4 +/- 32.1 pg/ml in serotype 2. This assay could predict the outcome of IFN therapy in both serotype 1 (P < 0.0001) and serotype 2 (P < 0.05). Thus, both the COBAS v2.0 assay and the HCV core protein assay showed that the viral load was an indicator of virologically sustained response in serotype 2 and in serotype 1.     

Detection and quantitation of HCV RNA using real-time PCR after automated sample processing

There is considerable evidence that the loss of hepatitis C virus (HCV) RNA during the first 3 months of treatment with pegylated interferon plus ribavirin is a prognostic marker of response to therapy. Real-time polymerase chain reaction (PCR) assays for quantifying HCV RNA in plasma or serum are now commercially available. The extraction of HCV RNA can also be automated. This report analyses the performance of the COBAS Ampliprep-COBAS Taqman 48 (CAP/CTM) real-time PCR assay and compares this new test with the COBAS Amplicor HCV Monitor v 2.0 assay (CAM). CAP/CTM was 100% specific. The assay was linear across a wide range of HCV RNA concentrations without sample dilution. The intra-assay variation was 0.3-3.3% and the interassay variation was 1.5-6.7%. A total of 118 clinical samples with different HCV genotypes were assayed using both methods. The results obtained using the two methods were well correlated (r = 0.89, P < 0.001). The mean difference [CAP/CTM-CAM] was 0.17 log IU/ml and it was not influenced by the HCV genotype or by the subtype. It is concluded that the new CAP/CTM system is adequate for quantifying HCV RNA in clinical practice.     

Evaluation of the invader assay for genotyping hepatitis C virus

The Invader 1.0 assay (Invader HCV Genotyping Assay, version 1.0; Third Wave Technologies, Inc., Madison, WI) has been developed for the rapid differentiation of hepatitis C virus (HCV) genotypes 1 to 6 based on sequence variation within the HCV 5' noncoding (NC) region. In the present study, we evaluated the compatibility of Invader 1.0 with the COBAS MONITOR (COBAS AMPLICOR HCV MONITOR Test, version 2.0; Roche Molecular Systems, Inc., Branchburg, NJ), COBAS AMPLICOR (COBAS AMPLICOR Hepatitis C Virus Test, version 2.0; Roche Molecular Systems, Inc.), and COBAS TaqMan (COBAS TaqMan HCV Test; Roche Molecular Systems, Inc.) assays. The minimum HCV RNA titers required for successful HCV genotyping (>/=90% success rate) were 1,000 IU/ml for COBAS MONITOR, 100 IU/ml for COBAS AMPLICOR, and 10 IU/ml for COBAS TaqMan. Invader 1.0 results obtained from unpurified COBAS TaqMan amplification products of 111 retrospectively selected clinical serum specimens (genotypes 1 to 6, with virus titers ranging from 15.1 to 2.1 x 10(7) IU/ml) showed 98% concordance with results obtained from the TRUGENE HCV 5' NC Genotyping Kit (Bayer HealthCare LLC, Tarrytown, NY), used in conjunction with COBAS AMPLICOR. Although the assay is sensitive, accurate, and easy to perform, additional optimization of the Invader 1.0 interpretive software (Invader Data Analysis Worksheet) may be necessary to reduce potential misidentification of HCV genotypes in low-titer specimens. In summary, Invader 1.0 is compatible with a variety of commercially available PCR-based HCV 5' NC region amplification assays and is suitable for routine HCV genotyping in clinical laboratories.     

Dynamic range of hepatitis C virus RNA quantification with the Cobas Ampliprep-Cobas Amplicor HCV Monitor v2.0 assay

Accurate quantification of hepatitis C virus (HCV) RNA is needed in clinical practice to decide whether to continue or stop pegylated interferon-alpha-ribavirin combination therapy at week 12 of treatment for patients with chronic hepatitis C. Currently the HCV RNA quantification assay most widely used worldwide is the Amplicor HCV Monitor v2.0 assay (Roche Molecular Systems, Pleasanton, Calif.). The HCV RNA extraction step can be automated in the Cobas Ampliprep device. In this work, we show that the dynamic range of HCV RNA quantification of the Cobas Ampliprep/Cobas Amplicor HCV Monitor v2.0 procedure is 600 to 200,000 HCV RNA IU/ml (2.8 to 5.3 log IU/ml), which does not cover the full range of HCV RNA levels in infected patients. Any sample containing more than 200,000 IU/ml (5.3 log IU/ml) must thus be retested after dilution for accurate quantification. These results emphasize the need for commercial HCV RNA quantification assays with a broader range of linear quantification, such as real-time PCR-based assays.     

Validation of an automated real-time PCR protocol for detection and quantitation of HIV and HCV genomes in semen

The ability to detect and quantify HIV and HCV genomes is important for checking spermatozoid preparation protocols also known as "sperm washing". But no commercial assay is available. A method was developed for detecting HIV and HCV in semen fractions using the COBAS Ampliprep and COBAS Taqman instruments. It will detect fewer than 200 copies of HIV RNA per ml of semen plasma and fewer than 200 copies/3 x 10(6) semen cells. The sensitivity for HCV is similar at more than 200 IU/ml and below 200 IU/3 x 10(6) semen cells. No inhibitor of PCR amplification was detected. This automated protocol permits a convenient, standardized testing for HIV and HCV in semen. The performance is the same as that of the previous generation of automated assays but the cost and operating time are both reduced.     

The role of core antigen detection in management of hepatitis C: a critical review.

Several assays in research format and two commercial assays for the detection of hepatitis C virus (HCV) core protein or HCV core antigen have been developed in recent years. In order to elucidate the role and significance of HCV core antigen detection in the diagnosis and management of hepatitis C, we reviewed 56 studies published in peer-reviewed journals until September 2004. Evaluations in transfusion settings showed that the HCV core antigen assay detects HCV infection, similarly as nucleic acid techniques (NAT), between 40 and 50 days earlier than the current third generation HCV antibody screening assays. HCV core antigen levels closely track HCV RNA dynamics, and allow clinical monitoring of a patient's therapy, independently of HCV genotype, however, mainly in the samples with HCV RNA levels above 20,000 IU/ml. Considering the lower sensitivity of HCV core antigen detection in comparison to NAT, the HCV core antigen assay is not practical for the determination of the end of treatment response and sustained viral response, but could be useful for the determination of early viral response in the pegylated interferon-alpha and ribavirin treated patients infected with HCV genotype 1. The HCV core antigen detection is a viable tool for study of hepatitis C pathogenesis. The HCV core antigen can be used as a marker of HCV replication in anti-HCV positive individuals in the areas of the world that cannot afford NAT and/or in the settings that are not equipped or competent to perform HCV RNA testing. Because the manufacturer of HCV core antigen assays recently stopped an active marketing of these assays in several countries, it will, unfortunately and probably, never be possible to determine the actual potential and usefulness of HCV core antigen testing in the management of hepatitis C.     

Improvement of sensitivity in the second generation HCV core antigen assay by a novel concentration method using polyethylene glycol (PEG)

A HCV core antigen (Ag) detection assay system, Lumipulse Ortho HCV Ag has been developed and is commercially available in Japan with a lower detection level limit of 50 fmol/l, which is equivalent to 20 KIU/ml in PCR quantitative assay. HCV core Ag assay has an advantage of broader dynamic range compared with PCR assay, however the sensitivity is lower than PCR. We developed a novel HCV core Ag concentration method using polyethylene glycol (PEG), which can improve the sensitivity five times better than the original assay. The reproducibility was examined by consecutive five-time measurement of HCV patients serum, in which the results of HCV core Ag original and concentrated method were 56.8 +/- 8.1 fmol/l (mean +/- SD), CV 14.2% and 322.9 +/- 45.5 fmol/l CV 14.0%, respectively. The assay results of HCV negative samples in original HCV core Ag were all 0.1 fmol/l and the results were same even in the concentration method. The results of concentration method were 5.7 times higher than original assay, which was almost equal to theoretical rate as expected. The assay results of serially diluted samples were also as same as expected data in both original and concentration assay. We confirmed that the sensitivity of HCV core Ag concentration method had almost as same sensitivity as PCR high range assay in the competitive assay study using the serially monitored samples of five HCV patients during interferon therapy. A novel concentration method using PEG in HCV core Ag assay system seems to be useful for assessing and monitoring interferon treatment for HCV.     

Impact of hepatitis C virus (HCV) genotypes on quantification of HCV RNA in serum by COBAS AmpliPrep/COBAS TaqMan HCV test, Abbott HCV realtime assay [corrected] and VERSANT HCV RNA assay

The VERSANT HCV RNA 3.0 (bDNA), COBAS AmpliPrep/COBAS TaqMan HCV, and Abbott ART HCV RealTime assays were compared for hepatitis C virus RNA quantification in 158 clinical specimens (genotypes 1 to 5). RNA values differed significantly between methods (P < 0.0001), and mean titer differences ranged from 0.01 to 0.50 log(10) IU/ml depending on the genotypes.     

Assessment of viral loads in patients with chronic hepatitis C with AMPLICOR HCV MONITOR version 1.0, COBAS HCV MONITOR version 2.0, and QUANTIPLEX HCV RNA version 2.0 assays

The correlation between response to antiviral therapy and pretreatment viral load in patients with chronic hepatitis C has prompted the development of quantitative assays to measure viral load. The aim of our study was to assess the clinical relevance of the newly developed semiautomated PCR system COBAS HCV MONITOR version 2.0 in comparison with (i) the AMPLICOR HCV MONITOR version 1.0 assay, which underestimates RNA concentration of hepatitis C virus (HCV) genotypes 2 to 6, and (ii) the QUANTIPLEX HCV RNA version 2.0 assay, which achieves equivalent quantification for each HCV genotype, with samples from 174 patients diagnosed with chronic hepatitis C before therapy. The level and range of quantification measured with AMPLICOR HCV MONITOR version 1.0 were 1 log lower than when measured with the COBAS HCV MONITOR version 2.0, at 0.261 x 10(6) RNA copies/ml (range, 0.001 x 10(6) to 2.50 x 10(6) RNA copies/ml) and 4.032 x 10(6) RNA copies/ml (range, 0.026 x 10(6) to 72.6 x 10(6) RNA copies/ml), respectively. The two assays showed a poor correlation (r(2) = 0.175). The level and range of quantification were similar when measured with the COBAS HCV MONITOR version 2.0 and QUANTIPLEX HCV RNA version 2.0 assays, at 3.03 x 10(6) RNA copies/ml (range, 0.023 x 10(6) to 72.6 x 10(6) RNA copies/ml) and 4.91 Meq/ml (range, 0.200 to 49.5 Meq/ml), respectively. The two assays showed a strong correlation (r(2) = 0. 686) for each HCV genotype. The duration of treatment (6 or 12 months) is modulated according to HCV genotype and viral load. Our results indicate that COBAS HCV MONITOR version 2.0 and QUANTIPLEX HCV RNA version 2.0 assays showing an equal dynamic range for each HCV genotype are suitable tools to assess patients before therapy.