Performance evaluation of the new Roche cobas AmpliPrep/cobas TaqMan HCV test, version 2.0, for detection and quantification of hepatitis C virus RNA. J Clin Microbiol. 2013;51:238-242. [PMID: 23152551 DOI: 10.1128/jcm.01729-12]

CALGB 80802 (Alliance): Impact of Sorafenib with and without Doxorubicin on Hepatitis C Infection in Patients with Advanced Hepatocellular Carcinoma

Sorafenib blocks nonstructural protein 5A (NS5A)-recruited c-Raf-mediated hepatitis C virus (HCV) replication and gene expression. Release of Raf-1-Ask-1 dimer and inhibition of Raf-1 via sorafenib putatively differ in the presence or absence of doxorubicin. Cancer and Leukemia Group B (CALGB) 80802 (Alliance) randomized phase III trial of doxorubicin plus sorafenib versus sorafenib in patients with advanced hepatocellular carcinoma (HCC), showed no improvement in median overall survival (OS). Whether HCV viral load impacts therapy and whether any correlation between HCV titers and outcome based on HCV was studied. In patients with HCV, HCV titer levels were evaluated at baseline and at multiple postbaseline timepoints until disease progression or treatment discontinuation. HCV titer levels were evaluated in relation to OS and progression-free survival (PFS). Among 53 patients with baseline HCV data, 12 patients had undetectable HCV (HCV-UN). Postbaseline HCV titer levels did not significantly differ between treatment arms. One patient in each arm went from detectable to HCV-UN with greater than 2 log-fold titer levels reduction. Aside from these 2 HCV-UN patients, HCV titers remained stable on treatment. Patients who had HCV-UN at baseline were 3.5 times more likely to progress and/or die from HCC compared with HCV detectable (HR = 3.51; 95% confidence interval: 1.58-7.78; P = 0.002). HCV titer levels remained unchanged, negating any sorafenib impact onto HCV titer levels. Although an overall negative phase III study, patients treated with doxorubicin plus sorafenib and sorafenib only, on CALGB 80802 had worse PFS if HCV-UN. Higher levels of HCV titers at baseline were associated with significantly improved PFS.

SIGNIFICANCE

Sorafenib therapy for HCC may impact HCV replication and viral gene expression. In HCV-positive patients accrued to CLAGB 80802 phase III study evaluating the addition of doxorubicin to sorafenib, HCV titer levels were evaluated at baseline and different timepoints. Sorafenib did not impact HCV titer levels. Despite an improved PFS in patients with detectable higher level HCV titers at baseline, no difference in OS was noted.

Efficacy and safety of alfosbuvir plus daclatasvir in Chinese patients with hepatitis C virus genotypes 1, 2, 3, and 6 infection: An open-label, phase 2 study

Alfosbuvir is a novel potent HCV NS5B polymerase inhibitor in development for the treatment of chronic HCV infection. Our previous studies indicated that alfosbuvir monotherapy was well-tolerated and druggable in healthy subjects and HCV-infected patients. Here, we evaluate the efficacy and safety of alfosbuvir in combination with daclatasvir in Chinese patients with HCV genotype 1, 2, 3 or 6. In this open-label study, patients with chronic HCV infection were randomly assigned with a 1:1:1 ratio to receive 12 weeks of daclatasvir 60 mg plus alfosbuvir at a dose of 400, 600 or 800 mg (Cohort A, B or C) daily. Randomization was stratified by HCV genotype and the presence or absence of cirrhosis at screening. The primary endpoint was a sustained virologic response 12 weeks after the end of treatment (SVR12). A total of 124 patients were enrolled in the study, all of whom were available for post-treatment week 12 assessments. SVR12 was achieved in 92.7% (38/41), 95.2% (40/42) and 100% (41/41) of patients in Cohort A, B and C respectively. The most common adverse events were hepatic steatosis, upper respiratory tract infection, hypercholesterolaemia, hypertriglyceridaemia, blood bilirubin increased, and total bile acids increased. There were no discontinuations due to adverse events, and no treatment-related serious adverse events were reported. Once-daily oral administration of alfosbuvir plus daclatasvir were highly effective and safe in Chinese patients infected with HCV genotype 1, 2, 3 or 6, suggesting this regimen could be a promising drug candidate for HCV treatment irrespective of genotype. (ClinicalTrials.gov number, NCT04070235).

Fully automated rapid quantification of Hepatitis C Virus RNA in human plasma and serum by integrated on-chip RT-qPCR and capillary electrophoresis

The quantification of hepatitis C virus (HCV) is essential for the management of chronic hepatitis C therapy. We have developed a fully automated microfluidic RT-qPCR system for rapid quantitative detection of HCV RNA in human EDTA-plasma and serum, and the performance of the method was assessed. The platform for the assay, µTASWako g1 Fully Automated Genetic Analyzer, performs automated sample preparation and RNA extraction, followed by amplification and detection on an integrated RT-qPCR-CE (capillary electrophoresis (CE)) microfluidic chip. The total assay time from sample input to data output is less than 120 minutes. The HCV assay has a linear quantitative range of 15 to 10⁷ IU/mL, with a limit of detection (LOD) of 10.65 IU/mL in EDTA-plasma and 12.43 IU/mL in serum. The assay has a reproducibility of SD ≤ 0.16 log₁₀ IU/mL and an accuracy of ≤ 0.22 log₁₀ IU/mL difference when compared to the assigned values. The main HCV genotypes 1 to 6 are detected with an accuracy of ± 0.3 log₁₀ IU/mL. The assay is specific for HCV RNA and is free of interference from non-HCV pathogens, elevated levels of anti-viral and anti-bacterial drugs, and common endogenous interferents. In the linear quantitative range, the assay is highly correlated with the Roche cobas AmpliPrep/cobas TaqMan HCV Test, version 2.0 (r² = 0.949). As the assay is highly sensitive, accurate and specific, and provides reliable quantification of HCV in plasma and serum, it can potentially be applicable for monitoring the therapy and management of HCV infection.

Serum‑derived hepatitis C virus can infect human glioblastoma cell line SF268 and activate the PI3K‑Akt pathway

Extra‑hepatic manifestations are frequently observed in hepatitis C virus (HCV)‑infected patients; however the underlying mechanisms remain largely unknown. In the present study, the human glioblastoma SF268 cell line (the precise origin of the cell type is not clear) was infected with HCV using HCV‑positive serum, and viral replication was assessed by immunofluorescence, reverse transcription‑polymerase chain reaction (PCR), quantitative PCR and western blotting following infection. HCV core protein and HCV RNA were detected in HCV‑positive serum‑infected SF268 cells at day 4 post‑infection, while no infection was observed in cells exposed to HCV‑negative serum. The mean HCV RNA levels at day 4 post‑infection were up to 5.00 IU/ml log10; however, HCV RNA and immunostaining for core protein were negative when cultured to day 6 or longer. The data suggest that human glioblastoma SF268 cells were transiently infected with HCV. AKT serine/threonine kinase phosphorylation was also detected in HCV‑infected SF268 cells at day 4 post‑infection. To the best of our knowledge, this is the first demonstration that a human glioblastoma cell line can be infected with serum‑derived HCV. The results provide evidence that HCV infection can occur in cells of the central nervous system. Neurological disorder‑associated phosphoinositide 3‑kinase‑AKT signaling pathway was activated in parallel with HCV infection, suggesting that SF268 may serve as an in vitro model for investigating HCV‑nervous system cell interactions.

Analysis of bodily fluids using vibrational spectroscopy: a direct comparison of Raman scattering and infrared absorption techniques for the case of glucose in blood serum

Analysis of biomarkers present in the blood stream can potentially deliver crucial information on patient health and indicate the presence of numerous pathologies.

Implementation and Preliminary Results of an Emergency Department Nontargeted, Opt-out Hepatitis C Virus Screening Program

BACKGROUND

Emergency department (ED) visits provide an opportunity for hepatitis C virus (HCV) screening for patients who otherwise might not be tested. We report on a novel nontargeted, opt-out HCV screening and linkage-to-care (LTC) program implemented in an urban ED.

METHODS

This is a descriptive analysis from 3 months (November 2016-January 2017) of a nontargeted, opt-out ED HCV screening and LTC program among patients at least 13 years old undergoing phlebotomy for clinical purposes. A multipurpose best practice advisory (BPA) alerted providers to the program and generated order labels. For patients who authorized testing, specimens were drawn in the ED for HCV antibody (Ab) and reflex confirmatory RNA tests. Public health navigators attempted to contact RNA-positive patients and arrange outpatient visits.

RESULTS

HCV Ab tests were performed on 3,808 patients, a 6,950% increase from preprogram. The proportion of HCV Ab test positivity was 13.2% (504/3,808, 95% confidence interval [CI] = 12.2%-14.3%) and of those 97.8% (493/504) had a follow-up RNA test performed. A total of 292 were confirmed positive for active infection, for an overall RNA positivity rate of 7.7% (95% CI = 6.8%-8.5%). Of those with active infection, 155 (53%) were outside the Centers for Disease Control and Prevention birth cohort for increased risk for HCV including 46 (15.8%, 95% CI = 11.8%-20.4%) who also did not report injection drug use. Linkage attempts were documented on 223 (76.4%) patients and appointments were scheduled for 102 (38% of attempted). Sixty-six patients attended their LTC visit (22.5% of all RNA-positive patients, 30% of linkage-eligible patients).

CONCLUSIONS

Nontargeted opt-out HCV testing can be successfully implemented in an ED setting. A number of patients diagnosed were outside traditional risk groups. Once diagnosed, an ED population may be difficult to engage in care, but a structured interdisciplinary program can successfully link patients to HCV care.

Outcome and adverse events in patients with chronic hepatitis C treated with direct-acting antivirals: a clinical randomized study

OBJECTIVE

New potent direct-acting antiviral (DAA) regimens against hepatitis C virus have been approved in recent years. However, information about the rate of adverse events (AEs) across different DAA regimens is limited. We aimed to evaluate differences in AEs and treatment efficacy in patients with chronic hepatitis C (CHC), genotype (GT) 1 or 3, randomized to two different treatment arms, correspondingly.

PATIENTS AND METHODS

We randomly assigned 96 patients in a 1 : 1 ratio, to treatment for 12 weeks with either paritaprevir/ombitasvir/ritonavir/dasabuvir/ribavirin (RBV) or ledipasvir/sofosbuvir (SOF)/RBV if infected with GT1 (72 patients) or to daclatasvir/SOF/RBV for 12 weeks or SOF/RBV for 24 weeks, if infected with GT3 (24 patients). Data on AEs were collected throughout the entire study period.

RESULTS

A total of 70 (97%) patients with CHC with GT1 and 20 (83%) patients with GT3 achieved cure. The GT3 treatment arm was prematurely terminated, owing to change in national treatment guidelines. Thus, only AEs for GT1 patients are described. AEs occurred in 70 (97%) GT1 patients, and most common AEs were anemia (n=56/78%), fatigue (n=53/74%), and headache (n=33/46%). No difference was observed in relation to treatment group (P=1.0), anemia (P=1.0), or liver cirrhosis (P=0.53). In seven (11%) patients, AEs assessed by the investigator to be possibly related to the DAA regimen were still present 12 weeks after treatment.

CONCLUSIONS

We found no difference in AEs possibly related to the DAA regimen in patients with CHC, but surprisingly, AEs possibly related to the DAA regimen persisted in a significant number of patients after treatment. This finding can be of importance for clinicians in relation to patient information concerning AEs possibly related to DAA treatment.

Evaluation of in vitro screening and diagnostic kits for hepatitis C virus infection

BACKGROUND

To detect infection by hepatitis C virus (HCV), a reliable kit with high sensitivity and specificity is indispensable. Detection kits for anti-HCV antibodies (anti-HCV) are used for screening, and quantification kits for HCV RNA and core antigen are used for definite diagnosis of HCV infection.

OBJECTIVES

We evaluated the performance of these kits using International Standards and a regional reference panel with HCV negative and positive specimens.

STUDY DESIGN

In vitro diagnostic kits (10 anti-HCV, two HCV RNA, and three HCV core antigen) were included.

RESULTS

Nearly all specimens in the regional reference panel were correctly identified by all anti-HCV detection kits (one false-positive was observed in one kit). Both HCV RNA quantification kits also correctly identified and quantified HCV RNA titers, without genotype-specific differences. Among the HCV core antigen kits, International Standard values were inconsistent. The sensitivities of these kits were insufficient to detect HCV in positive specimens in the regional reference panel.

CONCLUSIONS

In vitro diagnostic kits assessing anti-HCV and HCV RNA have sufficient sensitivities and specificities to screen and detect HCV infection. However, HCV core antigen quantification kits have some limitations in their sensitivities and consistencies for diagnosis of HCV infection. Quality control with International Standards and a regional reference panel is important to maintain the performances of diagnostic kits for HCV infection and to verify the clinical reliability of these kits.

Analytical and clinical performance of the Hologic Aptima HCV Quant Dx Assay for the quantification of HCV RNA in plasma samples

BACKGROUND

Chronic hepatitis C virus (HCV) infection can be effectively treated with directly acting antiviral (DAA) therapy. Measurement of HCV RNA is used to evaluate patient compliance and virological response during and after treatment.

OBJECTIVES

To compare the analytical performance of the Aptima HCV Quant Dx Assay (Aptima) and the COBAS Ampliprep/COBAS TaqMan HCV Test v2.0 (CAPCTMv2) for the quantification of HCV RNA in plasma samples, and compare the clinical utility of the two tests in patients undergoing treatment with DAA therapy.

STUDY DESIGN

Analytical performance was evaluated on two sets of plasma samples: 125 genotyped samples and 172 samples referred for quantification of HCV RNA. Furthermore, performance was evaluated using dilutions series of four samples containing HCV genotype 1a, 2b, 3a, and 4a, respectively. Clinical utility was evaluated on 118 plasma samples obtained from 13 patients undergoing treatment with DAAs.

RESULTS

Deming regression of results from 187 plasma samples with HCV RNA >2 Log IU/mL indicated that the Aptima assay quantified higher than the CAPCTMv2 test for HCV RNA >4.9 Log IU/mL. The linearity of the Aptima assay was excellent across dilution series of four HCV genotypes (slope of the regression line: 1.00-1.02). The Aptima assay detected significantly more replicates below targeted 2 Log IU/mL than the CAPCTMv2 test, and yielded clearly interpretable results when used to analyze samples from patients treated with DAAs.

CONCLUSIONS

The analytical performance of the Aptima assay makes it well suited for monitoring patients with chronic HCV infection undergoing antiviral treatment.

Chronic Hepatitis B, C, and D

Chronic hepatitis B, C, and D virus infections contribute significantly to the morbidity and mortality of immunocompromised individuals. To contextualize discussion of these infections in immunocompromised patients, this paper provides an overview of aspects of infection in normal hosts. It then describes differences in disease, diagnostic testing, and therapeutic management observed in immunocompromised patients.

Performance evaluation of the Aptima® HCV Quant Dx assay for hepatitis C virus (HCV) RNA detection and quantification in comparison to the Abbott RealTime HCV assay

BACKGROUND

The Aptima HCV Quant Dx assay (Aptima) is a real-time transcription-mediated amplification assay CE-approved for the diagnosis and monitoring of hepatitis C virus (HCV) infection.

OBJECTIVE

Aptima's analytical performance was compared to the Abbott RealTime HCV assay (RealTime) in a clinical routine setting.

STUDY DESIGN

Overall 295 clinical plasma samples (117 prospective/fresh; 178 retrospective/frozen) from HCV-infected patients were tested in Aptima and RealTime to determine concordance on qualitative and quantitative results. Linearity and precision at low viral loads (VLs; 0.8-3.3LogIU/mL) was tested using dilutions of the 5th WHO standard, in 10 and 20 replicates in the two assays, respectively. The ability to measure different HCV genotypes and accuracy were analyzed using the Seracare EQA panel.

RESULTS

Inter-assay agreement for qualitative results (prospective samples) was 88% (kappa=0.78). For the 127 samples with quantitative results in both assays, Aptima yielded on average slightly higher values (by 0.24LogIU/mL; Bland-Altman method) than RealTime. Concordance between assay results was excellent (R=0.98). At low VLs (0.8-3.3LogIU/mL), Aptima demonstrated good linearity and precision, similar to RealTime. Aptima detected and accurately quantified all main HCV genotypes.

CONCLUSIONS

Aptima demonstrated excellent precision, linearity, and accuracy in all genotypes tested. Good concordance was observed between Aptima and RealTime assays in clinical samples. The performance of the Aptima assay, on the fully automated Panther platform, makes it an excellent candidate for the detection and monitoring of HCV RNA in plasma and serum samples.

Differences between quantification of genotype 3 hepatitis C virus RNA by Versions 1.0 and 2.0 of the COBAS AmpliPrep/COBAS TaqMan HCV Test

Background:

Differences between the designs of hepatitis C virus (HCV) viral load assays can result in genotype-related variability in RNA quantification. We tested paired aliquots of plasma specimens from HCV-infected individuals using two versions (v1.0 and v2.0) of the Roche COBAS AmpliPrep/COBAS TaqMan HCV Test (CAP/CTM HCV) and noted variability between results for a subset of specimens; we then sought to determine whether discrepant results were more prevalent among specific HCV genotypes.

Methods:

Archived and prospectively-collected plasma samples from 114 unique patients were tested using CAP/CTM HCV v1.0 and v2.0. The HCV genotype result for each patient was determined by retrospectively reviewing laboratory records.

Results:

All (46/46) specimens with quantifiable viral loads from patients with genotype 1 or 2 infection had CAP/CTM HCV v1.0 and v2.0 results that were within 0.5 log

Conclusions:

In patients infected with HCV genotype 3, sequential CAP/CTM HCV viral load results should be compared with caution and interpreted in the context of the specific assay version used.

Quantitative nucleic acid amplification methods and their implications in clinical virology

Recently, a number of techniques have been approved for quantification of viral nucleic acids in clinical samples. Viral load (VL) tests have considerable importance in the management of patients and are widely used in routine diagnosis. In clinical virology, VL testing are important to monitor the antiviral treatment, to initiate preemptive therapy, to understand pathogenesis, and to evaluate the infectivity. These tests have now become a part of many diagnostic and treatment guidelines. Considering the various challenges for in-house viral testing related to the standardization, validation, and precision; they are gradually being replaced by the United States Food and Drug Administration (US FDA) cleared tests. This review summarizes the various viral quantification methods and also discusses the clinical applicability of these in human immunodeficiency virus, Hepatitis B virus, Hepatitis C virus, Cytomegalovirus, and Epstein Barr virus infected patients. Further the challenges and future perspectives of VL testing have also been discussed.

Analytical performance of the VERIS MDx system HCV assay for detecting and quantifying HCV RNA

BACKGROUND

The diagnosis of HCV relies on the detection of viral RNA.

OBJECTIVE

To evaluate the performance of the VERIS/MDx System HCV Assay, a new automated system for quantifying HCV RNA, and to compare with the COBAS^® Ampliprep/COBAS^® Taqman™ (CAPCTM) HCV Test version 2.0.

STUDY DESIGN

The limit of detection was determined by Probit analysis with the 3rd International WHO HCV standard and precision by assaying in duplicate control samples with HCV RNA concentrations of 7.9; 5.0; 3.4; 1.6 and 0logIU/ml over 20 days. Analytical specificity was assessed by assaying 180 samples from negative anti-HCV and HCV RNA blood donors and linearity with replicates of serial dilutions of a clinical plasma (6.4-0.6logIU/ml). We compared the VERIS MDx HCV and CAPCTM HCV assays by testing 209 samples.

RESULTS

The limit of detection was 6.1IU/ml [CI 95%: 5.0-8.3] and the precision, given by the standard deviation, was ≤0.11logIU/ml. Specificity was 100%. The linearity ranged from 1.5 to 6.4logIU/ml. Passing-Bablok regression analysis gave: VERIS logIU/ml=-0.33+[1.04× CAPCTM] logIU/ml, with biases for the 25th, 50th, 75th percentiles of 0.18, -0.10 and -0.06logIU/ml. The two assays were well correlated (ρ=0.92, p<0.001) and Bland-Altman analysis gave biases of 0.12, logIU/ml for genotype 1, -0.19 for genotype 2, -0.26 for genotype 3, and -0.77 for genotype 4.

CONCLUSION

The VERIS MDx HCV assay performed well. But, we observed an under-quantification of the genotype 4 samples.

APASL consensus statements and recommendations for hepatitis C prevention, epidemiology, and laboratory testing

The Asian Pacific Association for the Study of the Liver (APASL) convened an international working party on "APASL consensus statements and recommendations for management of hepatitis C" in March 2015 to revise the "APASL consensus statements and management algorithms for hepatitis C virus infection" (Hepatol Int 6:409-435, 2012). The working party consisted of expert hepatologists from the Asian-Pacific region gathered at the Istanbul Congress Center, Istanbul, Turkey on 13 March 2015. New data were presented, discussed, and debated during the course of drafting a revision. Participants of the consensus meeting assessed the quality of the cited studies. The finalized recommendations for hepatitis C prevention, epidemiology, and laboratory testing are presented in this review.

Hepatitis E in Children: A Position Paper by the ESPGHAN Hepatology Committee

BACKGROUND

Hepatitis E virus (HEV) is endemic in large parts of the developing world. Waterborne transmission of genotypes 1 or 2 commonly causes acute hepatitis, which is usually self-limited in healthy individuals. In addition, acute HEV infections also occur outside endemic areas, mostly related to foodborne transmission of HEV genotype 3. A growing number of publications in the last decade have reported chronic infection progressing to cirrhosis in immunosuppressed patients. It has also been suggested that HEV transmission may occur via contaminated blood products. This publication aims to provide recommendations for diagnosis, prevention, and treatment of HEV infection, particularly in children after solid organ transplantation.

METHODS

A systematic PubMed literature search on HEV infection from 1990 to January 2016 was performed focusing on pediatric studies. The existing body of evidence was reviewed and recommendations were agreed upon following discussion and unanimous agreement by all members of the ESPGHAN Hepatology Committee during a consensus meeting in January 2016. In the absence of randomized controlled studies these recommendations were considered to be expert opinions.

KEY RECOMMENDATIONS

Immunocompetent children with increased transaminases and/or extrahepatic manifestations should be considered for testing for evidence of HEV infection. Immunocompromised children with increased aminotransferases should be repeatedly tested for HEV and may require therapeutic intervention.

COBAS ® AmpliPrep/COBAS ® Taqman ® HCV Quantitative Test, version 2.0: an in vitro test for hepatitis C virus RNA quantification

The COBAS(®) AmpliPrep/COBAS(®) Taqman(®) HCV Quantitative Test, version 2.0, is an in vitro, fully automated, real-time, nucleic acid amplification test indicated for quantifying hepatitis C virus (HCV) RNA levels in the plasma/serum of patients infected with HCV of genotypes 1-6 who are receiving anti-viral therapy. By quantifying levels of HCV RNA in these patients, the test can be used early in the course of treatment to predict the likelihood of a sustained virologic response being achieved and can also be used to assess virologic response during treatment as part of response-guided therapy. The test has excellent sensitivity, high specificity and a broad linear range of quantitation. It correlates well with version 1.0 of the same test, but has the benefit of better sensitivity and genotype inclusivity and a smaller sample input volume. It also correlates well with other available HCV tests, including other quantitative real-time PCR tests (specifically the COBAS(®) Taqman(®) HCV Test, version 2.0, used with the high pure system, and the Abbott Realtime and Artus HCV QS-RGQ tests), the Versant(®) branched DNA quantitative test, the COBAS(®) Amplicor HCV Qualitative PCR Test and the Versant(®) HCV qualitative transcription-mediated amplification assay. The test is not indicated for HCV infection diagnosis or to screen for the presence of HCV in blood/blood products.

Evaluation of the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HCV Test, v2.0 and comparison to assays used in routine clinical practice in an international multicenter clinical trial: The ExPECT study

BACKGROUND

The COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v2.0 (CAP/CTM2) is used for HCV RNA viral load monitoring.

OBJECTIVES

The performance of the CAP/CTM2 was compared to other widely used tests, including a manual version of the assay (the COBAS(®) TaqMan(®) HCV Test, v2.0 for use with the High Pure System, HPS/CTM2) predominantly used during phase III clinical trials for the new direct acting antiviral therapies.

STUDY DESIGN

Low HCV RNA level comparisons were performed across tests (Abbott Realtime HCV Test, ART; COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v1.0, CAP/CTM1; CAP/CTM2; and HPS/CTM2) using dilutions of the 2nd HCV WHO International Standard. Additionally, the clinical performance of the CAP/CTM2 was evaluated with 421 leftover HCV RNA-positive routine clinical samples.

RESULTS

All quantifiable WHO dilutions were within ±0.3log10IU/mL of the expected results across tests and the analytical sensitivity resulted in a limit of detection of 12IU/mL (95% confidence interval, 10, 15). When clinical samples were tested the results for 87% (367 of 421) of all sample comparisons were within ±0.5log10IU/mL. When low viral load results (25-3500IU/mL) were compared, values obtained by the ART assay were significantly lower (p<0.0001) than those obtained with the CAP/CTM2.

CONCLUSIONS

The new CAP/CTM2 showed good accuracy with comparable sensitivity to comparator assays. The new kit is well-suited for use in the routine diagnostic laboratory, especially for accurate monitoring of patients receiving triple therapy or interferone-free regimens.

A complete molecular biology assay for hepatitis C virus detection, quantification and genotyping

INTRODUCTION

Molecular biology procedures to detect, genotype and quantify hepatitis C virus (HCV) RNA in clinical samples have been extensively described. Routine commercial methods for each specific purpose (detection, quantification and genotyping) are also available, all of which are typically based on polymerase chain reaction (PCR) targeting the HCV 5' untranslated region (5'UTR). This study was performed to develop and validate a complete serial laboratory assay that combines real-time nested reverse transcription-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP) techniques for the complete molecular analysis of HCV (detection, genotyping and viral load) in clinical samples.

METHODS

Published HCV sequences were compared to select specific primers, probe and restriction enzyme sites. An original real-time nested RT-PCR-RFLP assay was then developed and validated to detect, genotype and quantify HCV in plasma samples.

RESULTS

The real-time nested RT-PCR data were linear and reproducible for HCV analysis in clinical samples. High correlations (> 0.97) were observed between samples with different viral loads and the corresponding read cycle (Ct - Cycle threshold), and this part of the assay had a wide dynamic range of analysis. Additionally, HCV genotypes 1, 2 and 3 were successfully distinguished using the RFLP method.

CONCLUSIONS

A complete serial molecular assay was developed and validated for HCV detection, quantification and genotyping.

Hepatitis C virus core antigen testing: Role in diagnosis, disease monitoring and treatment

While hepatitis B virus (HBV) screening relies on hepatitis B surface antigen to confirm HBV infection since the early days of hepatitis B disease management, hepatitis C virus (HCV) infection screening is based on anti-HCV testing which does not discriminate active from past infection. Thus to confirm infection HCV RNA testing has been required; recently a HCV core antigen assay became widely commercially available which could serve to confirm infection. That assay is less sensitive than current HCV RNA assays, but as more than 50% of anti-HCV positive persons will be HCV core antigen positive, HCV core antigen testing can be a cost effective and reflex test to confirm HCV infection in anti-HCV positive individuals and will be easier as it can be applied on the same platform. For treatment monitoring, more data need to be generated, but the early data available at present suggest that HCV core antigen may be an alternative to HCV RNA monitoring. With direct antivirals, HCV core antigen could even be superior to HCV RNA testing, as direct antivirals might already prevent virus formation when HCV core antigen is still produced and thereby correlates better with eventual viral clearance.

Comparison of the QIAGEN artus HCV QS-RGQ test with the Roche COBAS Ampliprep/COBAS TaqMan HCV test v2.0 for the quantification of HCV-RNA in plasma samples

BACKGROUND

Quantification of Hepatitis C Virus (HCV)-RNA is important for the clinical management of patients undergoing antiviral therapy.

OBJECTIVES

To compare the quantification of clinical plasma samples by the Roche COBAS AmpliPrep/COBAS TaqMan HCV test v2.0 and the artus HCV QS-RGQ test.

STUDY DESIGN

HCV-RNA viral load in 155 plasma samples from HCV-seropositive individuals was determined using the COBAS test and retrospectively with the artus. Furthermore, a dilution series of an Acrometrix standard was tested with both tests in replicates of five to assess differences in limit of detection and precision.

RESULTS

Two clinical samples showed inhibition using the artus test and were excluded from analysis. Of the clinical samples, 20 tested negative in both tests, 7 tested positive in the COBAS test and negative in the artus test, and 126 samples were quantified by both tests. The mean overall difference between tests (artus-COBAS) was 0.27 log IU/mL. The mean difference of quantification varied little across genotype 1a, 1b, 2b and 3a (range: +0.15 to +0.35 log IU/mL). Both tests were precise (%CV at 1000 IU/mL 1.1 and 1.8 for the COBAS and artus test, respectively).

CONCLUSIONS

The limit of detection appeared lower in the COBAS test than the artus test when analyzed from a limited number of replicates. Both tests were precise with the artus test quantifying higher than the COBAS test on average. It is therefore recommended to monitor individual patients with the same test throughout treatment.

HCV RNA detection in HCV antibody-positive patients with the COBAS AmpliPrep/COBAS TaqMan HCV test, v2.0 in comparison with FDA-approved nucleic acid tests

BACKGROUND

Analysis of hepatitis C virus (HCV) RNA levels is critical for assessing the efficacy of antiviral therapy and the achievement of a sustained virologic response.

OBJECTIVE AND STUDY DESIGN

This study evaluated the clinical performance of the COBAS AmpliPrep/COBAS TaqMan HCV quantitative test, version 2.0 (TAQMAN v2.0) with the COBAS AmpliPrep/COBAS TaqMan HCV quantitative test, version 1.0 (TAQMAN v1.0), the VERSANT HCV qualitative assay (VERSANT), and the COBAS AMPLICOR HCV test, v2.0 (AMPLICOR) qualitative test for the detection of HCV RNA in serum or EDTA plasma from patients who are or have been infected with HCV and carry HCV antibodies.

RESULTS

A total of 277 participants were evaluable for the percent agreement analysis of the TAQMAN v2.0 with the VERSANT and with the AMPLICOR. The overall percent agreement between the TAQMAN v2.0 and the VERSANT or the AMPLICOR was 99.3% (95% CI: 97.4%, 99.8%) or 98.9% (95% CI: 96.9%, 99.6%), respectively. The overall percent agreement between the TAQMAN v2.0 and the TAQMAN v1.0 when 267 of the original samples were assessed was 98.9% (95% CI=96.7%, 99.6%).

CONCLUSION

The TAQMAN v2.0 demonstrated high correlation with the previously approved HCV RNA quantitative and qualitative tests.

Tools for the diagnosis of hepatitis C virus infection and hepatic fibrosis staging

Hepatitis C virus (HCV) infection represents a major public health issue. Hepatitis C can be cured by therapy, but many infected individuals are unaware of their status. Effective HCV screening, fast diagnosis and characterization, and hepatic fibrosis staging are highly relevant for controlling transmission, treating infected patients and, consequently, avoiding end-stage liver disease. Exposure to HCV can be determined with high sensitivity and specificity with currently available third generation serology assays. Additionally, the use of point-of-care tests can increase HCV screening opportunities. However, active HCV infection must be confirmed by direct diagnosis methods. Additionally, HCV genotyping is required prior to starting any treatment. Increasingly, high-volume clinical laboratories use different types of automated platforms, which have simplified sample processing, reduced hands-on-time, minimized contamination risks and human error and ensured full traceability of results. Significant advances have also been made in the field of fibrosis stage assessment with the development of non-invasive methods, such as imaging techniques and serum-based tests. However, no single test is currently available that is able to completely replace liver biopsy. This review focuses on approved commercial tools used to diagnose HCV infection and the recommended hepatic fibrosis staging tests.

Performance characteristics of the COBAS Ampliprep/COBAS TaqMan v2.0 and the Abbott RealTime hepatitis C assays - implications for response-guided therapy in genotype 1 infections

BACKGROUND

With the advent of the protease inhibitors boceprevir and telaprevir a novel therapy approach for HCV genotype 1 infected subjects has become standard of care. Quantification of HCV viral load (VL) represents an important predictor of treatment response.

METHODS

Two different real-time PCR platforms, the COBAS Ampliprep/COBAS TaqMan v2.0 (CAP-CTM v2.0) and the Abbott RealTime (ART) HCV assay are most widely used. We performed a comparative evaluation of both systems focusing on genotype 1 HCV quantification using clinical specimens, the fourth WHO International Standard for HCV and the Paul Ehrlich National Standard, respectively.

RESULTS

The HCV VL assays showed an excellent overall agreement in the clinical specimens studied (R(2)=0.912). Discrepant results were obtained at the low VL end. Four samples tested negative with CAP-CTM v2.0 but were detectable with ART and two samples were undetectable with ART but tested positive with CAP-CTM v2.0. The coefficient of variation in replicate measurements of both reference materials was higher for CAP-CTM v2.0 as compared with ART at the clinical decision point for boceprevir (≥100 IU/ml), but was similar for the two assays at the clinical decision point for telaprevir (≥1,000 IU/ml). The tendency for underestimation of the diluted standards was higher for ART than for CAP-CTM v2.0.

CONCLUSIONS

Although both assays allowed accurate determination of VL levels in clinical samples, careful interpretation of results at the low VL end is essential. Furthermore, discontinuation of therapy based on single HCV RNA measurement should be carefully reconciled, unless the issue of assay variability has been addressed adequately.

Advances in the Diagnosis and Monitoring of Hepatitis C Virus Infection

Hepatitis C virus (HCV) infection represents a major health problem worldwide. Approximately 350,000 people die every year from hepatitis C related diseases. Antiviral therapy is given to prevent such complications. Advances in serological and molecular assays greatly improved the diagnosis of hepatitis C virus infection and the management of chronically infected patients. Sensitive real-time PCR methods are currently used to monitor the response to antiviral therapy, to guide treatment decisions, and to assess the sustained virological response 24 weeks after the end of therapy. HCV genotyping is part of the pretreatment evaluation. Determination of HCV genotype is important both for tailoring antiviral treatment and for determining treatment duration. It predicts also response to therapy. With the recent introduction of the serine protease inhibitors telaprevir and boceprevir, approved for the treatment of genotype 1 chronic hepatitis C in combination with INF-a and ribavirin, subtyping has become clinically relevant. Indeed, subtypes 1a and 1b may respond differently to current telaprevir-based or boceprevir-based triple therapy. This review summarizes the most recent advances in the diagnosis and monitoring of HCV chronic infection.

Detection limit of architect hepatitis C core antigen assay in correlation with HCV RNA, and renewed confirmation algorithm for reactive anti-HCV samples

BACKGROUND

hepatitis C infections are detected by anti-HCV screening tests. Reactive anti-HCV results give no information about the presence or absence of hepatitis C viruses, or of unspecific reactivity. To obtain information about the viral load, HCV RNA measurements, following a reactive anti-HCV result, are performed in well equipped and specialised laboratories. Anti-HCV immunoblots are the only means to exclude non specific reactivity. The measurement of HCV core antigen (HCV-Ag), as an alternative to HCV RNA, is discussed, as it can be analysed on the same instrument as anti-HCV.

OBJECTIVES

The detection limit of HCV-Ag is crucial to use it in lieu of HCV RNA, in regard of the different genotypes. A renewed algorithm is proposed to exclude unspecific reactivity of anti-HCV.

STUDY DESIGNS

Samples were tested on Architect i2000SR (Abbott) for anti-HCV and HCV-Ag. HCV RNA measurements were obtained by Cobas Ampliprep/Taqman (Roche) or m2000rt(®) (Abbott).

RESULTS AND CONCLUSIONS

Comparison between HCV-Ag and HCV RNA from 126 samples of 101 patients with chronic hepatitis C gave linear regression R(2) 0.89, slope 0.885 and intercept -2.258, which were independent of the genotypes. The detection limit of HCV-Ag was between 2.4 and 4.5 Log(10)IU/mL. A renewed algorithm for confirmation of reactive anti-HCV results is proposed: active or resolved hepatitis C infections or false reactivity can be differentiated by sequenced reflex testing due to HCV-Ag, anti-HCV immunoblot and HCV RNA.