RealTime Hepatitis C Virus Research Articles

Comparison of diagnostic performance among Abbott RealTime HCV Genotyping II, Abbott HCV Genotype plus RUO, and Roche Cobas HCV Genotyping assays for hepatitis C virus genotyping.

Comparison of diagnostic accuracy for commercial hepatitis C virus (HCV) genotyping (Abbott RealTime HCV Genotyping II, Roche Cobas Genotyping) and investigational Abbott HCV Genotype plus RUO assays designed to discriminate genotype (GT)-1a, 1b or 6 in cases of ambiguous GT from the Abbott commercial assay remains limited. 743 HCV-viremic samples were subjected to analysis using Abbott and Roche commercial as well as Abbott HCV Genotype plus RUO assays. Next-generation sequencing (NGS) targeting core region was employed as the reference standard. Diagnostic accuracy was reported as the number of participants (percentages) along with 95% confidence intervals (CIs). Using NGS, 741 samples (99.7%) yielded valid genotyping results. The diagnostic accuracies were 97.6% (95% CI: 96.1%-98.5%) and 95.3% (95% CI: 93.4%-96.6%) using Abbott and Roche commercial assays (p = 0.0174). Abbott commercial assay accurately diagnosed HCV GT-6a and 6w, whereas Roche commercial assay accurately diagnosed HCV GT-6a. Both assays demonstrated low accuracies for HCV GT-6b, 6e, 6g, and 6n. Abbott HCV Genotype plus RUO assay discriminated 13 of the 14 samples (92.9%; 95% CI: 64.2%-99.6%) that yielded ambiguous GT. Both assays were capable of diagnosing mixed HCV infections when the minor genotype comprised >8.4% of the viral load. The diagnostic performance of commercial HCV genotyping assays is commendable. Abbott assay demonstrated superior performance compared to Roche assay in diagnosing HCV GT-6. Abbott HCV Genotype plus RUO assay aids in discriminating ambiguous GT. Both commercial assays are proficient in diagnosing mixed HCV infections at a cut-off viral load of 8.4% in minor genotype.

Hepatitis C viral load and genotypes distribution among chronically infected patients in Morocco

PurposeIn Morocco, the hepatitis C virus (HCV) genotypic distribution is poorly studied and not continuously updated. The aim of this study is to characterize HCV genotypes diversity and dynamics in Morocco. MethodsA retrospective study carried out between 2003 and 2020 on 2101 patients HCV-positive at the molecular biology laboratory of Pasteur Institute of Morocco (IPM), involving HCV quantification through real-time PCR (RT-PCR) and HCV genotyping through reverse hybridization. All the 2101 patients had a viral load higher than 15 IU/mL. Alanine transaminase (ALT) levels and Fibrotest were performed in 150 patients. ResultsThe 2101 analyzed patients had a mean age of 59.52 ± 12.98 years. The average viral load was 5.23 ± 0.82 log IU/mL, and females were more affected than males (sex-ratio = 0.75, p < 0.05). Genotypes 1 (54.18 %) and 2 (42.98 %) were the most prevalent, while genotypes 3, 4 and 5 were rarely found. HCV subtypes were distributed as follows: 1b (37.74 %), 2a/2c (28.18 %), 2 UC (14.80 %), 1 UC (9.47 %), 1a (5.14 %), 1a/1b (2.43 %), 4 UC (0.90 %), 3 UC (0.57 %), 3a (0.48 %), 4a (0.14 %), 5 UC (0.10 %), and 5a (0.05 %). Genotype 3 was detected for the first time in our country in 2013 and increased over time. Advanced liver fibrosis was associated with genotype 1b followed by genotype 2a/2c, with genotype 1b demonstrates a propensity for heightened virulence (p < 0.05) in the present study. ConclusionOur study reports the most recent data on HCV genotypes distribution in Morocco and the importance of analyzing HCV variability as it offers insights into the virus's dynamics in the population, enabling the monitoring of new migratory flows and their influence on the transition's rate to chronic infection.

Diagnostic Performance and Usability of the Genedrive® HCV ID Kit in Two Decentralized Settings in Cameroon and Georgia.

Point-of-care diagnostics have the potential to increase diagnosis and linkage to care and help reach the WHO targets to eliminate hepatitis C virus (HCV) by 2030. Here, we evaluated the diagnostic accuracy of Genedrive HCV ID assay for the qualitative detection of HCV RNA in decentralized settings in two low- and middle-income countries using fresh plasma specimens from 426 participants. The Abbott RealTime HCV assay was used as the gold standard. Genedrive HCV ID assay was conducted by different users. Users also completed questionnaires to assess the usability of Genedrive. At detection thresholds of 12 IU/mL or 30 IU/mL, 1000 IU/mL, and 2362 IU/mL, the sensitivity was 96.2% (95% CI: 92.7–98.4), 100% (98.2–100), and 100% (98.2–100), respectively; the specificity was 99.5% (95% CI: 97.4–100), 99.5% (97.5–100), and 98.7% (96.1–100), respectively. All genotypes detected using the gold-standard assay were also detected with Genedrive. Users found Genedrive easy to use. Genedrive is a simple and accurate test to confirm chronic HCV infection in decentralized, real-life, resource-limited settings. This novel diagnostic tool could contribute to closing the current gap in HCV diagnosis.

Comparative performance of two commercial sample-to-result systems for hepatitis C virus quantitation and genotyping

ABSTRACT Objectives Accurate assays for hepatitis C virus (HCV) quantitation and genotyping are important for the management of HCV infection. In this study, we evaluated the performance of cobas HCV and cobas HCV GT assays (Roche) for HCV quantitation and genotyping on the cobas 4800 System. Methods We compared the performance of the cobas HCV assays with another commercial system (Abbott m2000) using a panel of well-characterized patient samples and proficiency testing samples. Results The limit-of-detection of the cobas HCV assay in our center was higher (15 IU/mL) than the manufacturer claim (9.2 IU/mL). The assay showed high analytical specificity, accuracy, precision, and linearity. Performance was congruent with the RealTime HCV assay (Abbott). For genotyping, the cobas HCV GT assay only showed moderate agreement with the RealTime HCV Genotype II assay (kappa = 0.550). The cobas assay outperformed the RealTime assay for typing HCV genotypes 1b and 6 (p = 0.033). Conclusion Our results confirm that the cobas 4800 System is a reliable platform for HCV quantitation and genotyping. The cobas HCV GT assay is a good choice for genotype 1b/6 endemic areas in east Asia, clearly outperforming the RealTime HCV Genotype II assay.

Indeterminate Prediction of Hepatitis C Virus Genotype by Commercial Real-Time Polymerase Chain Reaction Assay Resolving by Sequencing to Avoid the Consequence of Inaccurate Typing.

Pakistan is ranked second highest after Egypt in hepatitis C virus (HCV) infection. Accurate typing is mandatory to be compliant with the World Health Organization strategy to eliminate HCV infection in 2030. We characterized the HCV genotypes using Abbott real-time polymerase chain reaction assay and indeterminate samples were sequenced. We also investigated the distribution of HCV genotype among different age groups and gender in chronic HCV patients. One thousand thirteen samples were tested for HCV genotyping using Abbott real-time HCV genotyping assay. RNA extraction from plasma was done using the m2000sp platform. The amplification and detection of genotypes was done on m2000rt instrument. The lower limit of detection assay is 500 IU/mL. The indeterminate genotypes were analyzed by sequencing of the NS5B region. We found genotype 1 in 1.68%, genotype 1b in 0.89%, genotype 1a in 0.79%, genotype 2 in 0.6, genotype 3 in 94.37%, genotype 4 in 0.4%, genotype 5 in 0.09%, and indeterminate genotype result were found in 1.18%. Abbott assay could not identify 12 samples of genotype 3 (1.18%) and gave the indeterminate result. It also fails to assign some of the samples of genotype 1 into 1a and 1b. The indeterminate genotypes were resolved by sequencing followed by phylogenetic analysis. Genotype 3 is the predominant genotype and significantly higher in females as compared with males. Genotype 1a is more common in males than in females. Indeterminate HCV genotypes on sequencing analysis identify as genotype 3a and likewise subtype of genotype1 as 1a.

Evaluation of a hepatitis C virus core antigen assay from venepuncture and dried blood spot collected samples: A cohort study.

The global scale-up of hepatitis C virus (HCV) diagnosis requires simplified and affordable HCV diagnostic pathways. This study evaluated the sensitivity and specificity of the HCV Architect core antigen (HCVcAg) assay for detection of active HCV infection in plasma and capillary whole blood dried blood spots (DBS) compared with HCV RNA testing in plasma (Abbott RealTime HCV Viral Load). Samples were collected from participants in an observational cohort enrolled at three sites in Australia (two-drug treatment and alcohol clinics and one homelessness service). Of 205 participants, 200 had results across all samples and assay types and 186 were included in this analysis (14 participants receiving HCV therapy were excluded). HCV RNA was detected in 29% of participants ([95% CI: 22.6-36.1], 54 of 186). The sensitivity of HCVcAg for detection of active HCV infection in plasma was 98.1% (95% CI: 90-100) and 100% (95% CI: 93-100) when compared to HCV RNA thresholds of ≥12 and ≥1000IU/mL, respectively. The sensitivity of the HCVcAg assay for detection of active HCV infection in DBS was 90.7% (95% CI: 80-97) and 92.5% (95% CI: 82-98) when compared to HCV RNA thresholds of ≥12 and ≥1000IU/mL, respectively. The specificity of HCV core antigen for detection of active infection was 100% (95% CI: 97-100) for all samples and RNA thresholds. These data indicate that the detection of HCVcAg is a useful tool for determining active HCV infection; to facilitate enhanced testing, linkage to care and treatment particularly when testing plasma samples are collected by venepuncture.

The new Xpert HCV viral load real-time PCR assay accurately quantifies hepatitis C virus RNA in serum and whole-blood specimens

Background: Sensitive and accurate hepatitis C virus (HCV) RNA detection and quantification are essential to diagnose and monitor the virological response to antiviral treatment and the emergence of resistance. Objective and study design: The aim of this study was to assess the ability of the new Xpert HCV Viral Load assay to accurately detect and quantify HCV RNA in serum and in whole blood collected on dried blood spot (DBS). Serum and whole blood from a large series of patients chronically infected with different HCV genotypes were tested in parallel for HCV RNA detection and quantification. Results: A significant relationship between HCV RNA levels measured with the Xpert HCV Viral Load assay and the two commercial real-time PCR comparators (Abbott RealTime HCV test and Cobas AmpliPrep/Cobas Taqman HCV 2.0 test) was found in serum as well as in whole blood specimens. Conclusions: The Xpert HCV Viral Load assay accurately quantifies HCV RNA regardless of the HCV genotype and can thus confidently be used to detect active HCV infection in serum and in whole blood specimens.

The acceptability of serum sample storage for hepatitis C viral load analysis in chronic hepatitis C patients

The detectable time duration of stored serum sample containing hepatitis C virus (HCV) remains to be elucidated. This study aimed to elucidate the viral load changes of the stored serum samples under 4°C conditions. We measured the viral loads collected from 13 patients (8 males, age = 60.5 ± 17.5 years). The samples were kept under 4°C conditions before analysis. Besides baseline viral load, the samples then were measured at days 3, 5, 7, 9, and 11 after collection, respectively. The measured viral loads at different time points were compared with baseline samples by using the Abbott RealTime HCV Assay in an m2000 PCR System. The viral loads of the 13 patients ranged between 0.151 and 10 648.491 KIU/mL at baseline. There were no significant differences in viral load changes between the baseline and the samples of other time points. The differences were within 0.45 log10 IU/mL (P &gt; 0.05) at different time points. The study demonstrated that serum samples kept at 4°C for 11 days were acceptable for molecular analysis.

Evaluation of Dried Blood Spots as a Feasible Alternative to Plasma for the Detection and Quantification of Hepatitis C Virus in a Tropical Setting: A Pilot Study

AbstractIntroduction: Confirmatory diagnosis of hepatitis C virus (HCV) infection (HCV RNA detection) is essential before start of the therapy. HCV RNA detection is not available in many parts of India. Shipment of plasma from distant places to referral laboratories may affect HCV RNA titres. Dried blood spots (DBS) provide an easy alternative for transporting samples to centres where HCV RNA testing is done. Aim: Evaluation of DBS as a feasible alternative to plasma for HCV diagnosis. Methods: In this cross-sectional study, 40 consecutive patients’ blood samples were collected from patients referred from the Liver Clinic. Whole blood was spotted onto two Whatman 903TM cards. One card was incubated at ≥37°C and other at 4°C for 15 days, after drying. DBS was eluted and run in Abbott RealTime HCV assay. HCV was also quantified using the Abbott ARCHITECT HCV core antigen assay for 29 of the study patients. Results were compared with normal plasma values. Results: The median log HCV RNA value (in log10 IU/mL) of plasma was 5.74, with normalised DBS it was 4.92 (≥37°C) and 4.66 (4°C); difference in plasma and DBS median log values was 0.82 (≥37°C) and 1.08 (4°C) logs, respectively. Interclass correlation values were 0.943, P < 0.0001 (≥37°C) and 0.950, P < 0.0001 (4°C), showing high agreement. The median HCV core antigen value (in fmol/L) for plasma was 325.35, whereas it was 4.77 (≥37°C) and 4.64 (4°C) for DBS samples. Conclusions: DBS can be used for sampling patients from distant resource-limited settings as an alternative to plasma for HCV RNA estimation. Larger studies are required to evaluate the feasibility of DBS in the Indian subcontinent, especially for HCV core antigen estimation.

Hepatitis C virus surveillance and identification of human pegivirus 2 in a large Cameroonian cohort

SummaryThe prevalence of chronic hepatitis C virus (HCV) and the presence of human pegivirus 2 (HPgV‐2) have not been examined in Cameroon, although HCV has been associated with HPgV‐2 infections previously. Herein we aimed to characterize the burden and genetic diversity of HCV and the presence of HPgV‐2 in Cameroon. Retrospective plasma specimens collected from N = 12 369 consenting subjects in South Cameroon from 2013 to 2016 were included in the study. The majority (97.1%) of participants were patients seeking health care. All specimens were screened for HCV using the Abbott RealTime HCV viral load assay and positive specimens with remaining volume were also screened for HPgV‐2 antibodies on the Abbott ARCHITECT instrument, followed by molecular characterization. Overall, HCV RNA was detected in 305 (2.47%; 95% CI: 2.21%‐2.75%) specimens. Notably, the prevalence of HCV RNA was 9.09% amongst participants over age 40 and 3.81% amongst males. Phylogenetic classification of N = 103 HCV sequences identified genotypes 1 (19.4%), 2 (15.5%) and 4 (65.1%) within the study cohort. Amongst HCV RNA‐positive specimens, N = 28 (10.6%; 95% CI: 7.44%‐14.90%) specimens also had detectable HPgV‐2 antibodies. Of these, N = 2 viremic HPgV‐2 infections were confirmed by sequencing and shared 93‐94 median % identity with strains found on other continents. This is the first study to determine the prevalence of chronic HCV in Cameroon, and the discovery of HPgV‐2 in this study cohort expands the geography of HPgV‐2 to the African continent, indicating a widespread distribution exists.

Clinical significance of detectable and quantifiable HCV RNA at the end of treatment with ledipasvir/sofosbuvir in GT1 patients.

AASLD/IDSA treatment guidelines for hepatitis C virus (HCV) infection state that testing for quantitative HCV RNA can be considered at the end of antiviral treatment (EOT) with interferon-free regimens. However, it remains unclear how to respond to a detectable or even quantifiable HCV RNA result. The aim of this study was to analyse the frequency and predictive value of detectable and quantifiable HCV RNA results at the EOT in patients with HCV genotype 1 infection treated with ledipasvir (LDV) and sofosbuvir (SOF)±ribavirin (RBV) in a large real-world cohort. A retrospective analysis of the DHC-R (Deutsches Hepatitis C-Register, German Hepatitis C-Registry) cohort was performed including all patients who were treated with LDV/SOF±RBV and in whom HCV RNA testing was done with either the Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) or the Abbott RealTime HCV assay (ART). The frequency of detectable HCV RNA at the EOT was 7% in this real-world study involving 471 patients. Furthermore, 3% of the patients (n=14/471) even had quantifiable viral load at the EOT. Detectable and quantifiable results were more frequent if the ART was used for testing. However, SVR was achieved by 32/33 patients (97%) with detectable and even by all 14 patients (100%) with quantifiable HCV RNA results at the EOT. Detectable and even quantifiable HCV RNA results are quite frequent if highly sensitive HCV RNA assays are used. However, treatment prolongation is not indicated, as SVR rates remain high in these patients.

Indeterminate genotypes of hepatitis C virus by the Abbott RealTime HCV Genotype II assay in Morocco. About eight cases resolved by a sequencing method.

The early detection and genotyping of the hepatitis C virus (HCV) are important in the management of this infection. The genotype is the major factor influencing treatment decisions. That's why it is necessary to use fast and accurate methods in its determination. This study reports, over a period of 3 years (from May 2012 to July 2015), the percentage of indeterminate genotypes by the Abbott RealTime HCV Genotype II test and their results using a sequencing technique. Of 309 samples of 309 patients tested, 11 were indeterminate (4.4%). There were three cases of cross-reactivity (1b/4 in one case, 2/5 in two cases) and a possible co-infection 1 + 4. Among those indeterminate genotypes, cross-reactivities and co-infections, ten samples were tested by sequencing. The results were for four of them a 1d subtype, five were a 2i subtype and one was a 2l subtype. These results support the thesis of complementarity between the two methods: genotyping for the detection of mixed reactions and sequencing for resolving indeterminate cases by genotyping.

Development and clinical validation of the Genedrive point-of-care test for qualitative detection of hepatitis C virus

ObjectiveRecently approved direct acting antivirals provide transformative therapies for chronic hepatitis C virus (HCV) infection. The major clinical challenge remains to identify the undiagnosed patients worldwide, many of whom live...

Evaluation of the Xpert HCV Viral Load Finger-Stick Point-of-Care Assay.

Point-of-care hepatitis C virus (HCV) RNA testing is advantageous, enabling diagnosis of active infection in a single visit. This study evaluated the sensitivity and specificity of the Xpert HCV Viral Load Finger-Stick assay (Xpert HCV VL FS) for HCV RNA detection (finger-stick) and the Xpert HCV Viral Load assay (plasma) compared with the Abbott RealTime HCV Viral Load assay by venepuncture. Plasma and finger-stick capillary whole-blood samples were collected from participants in an observational cohort in Australia. Of 223 participants enrolled, HCV RNA was detected in 40% of participants (85 of 210) with available Xpert HCV Viral Load testing. Participants receiving HCV therapy were excluded from subsequent analyses (n = 16). Sensitivity of the Xpert HCV Viral Load assay for HCV RNA quantification in plasma collected by venepuncture was 100.0% (95% confidence interval [CI] 96.9%-100.0%) and specificity was 100.0% (95% CI, 94.4%-100.0%). Sensitivity of the Xpert HCV VL FS assay for HCV RNA quantification in samples collected by finger-stick was 100.0% (95% CI, 93.9%-100.0%) and specificity was 100.0% (95% CI, 96.6%-100.0%). The Xpert HCV VL FS test can accurately detect active infection from a finger-stick sample in 1 hour allowing single-visit HCV diagnosis.

Impact of inter-genotypic recombination and probe cross-reactivity on the performance of the Abbott RealTime HCV Genotype II assay for hepatitis C genotyping

The Abbott RealTime HCV Genotype II assay (Abbott-RT-HCV assay) is a real-time PCR based genotyping method for hepatitis C virus (HCV). This study measured the impact of inter-genotypic recombination and probe cross-reactivity on the performance of the Abbott-RT-HCV assay. 517 samples were genotyped using the Abbott-RT-HCV assay over a one-year period, 34 (6.6%) were identified as HCV genotype 1 without further subtype designation raising the possibility of inaccurate genotyping. These samples were subjected to confirmatory sequencing. 27 of these 34 (79%) samples were genotype 1b while five (15%) were genotype 6. One HCV isolate was an inter-genotypic 1a/4o recombinant. This is a novel natural HCV recombinant that has never been reported. Inter-genotypic recombination and probe cross-reactivity can affect the accuracy of the Abbott-RT-HCV assay, both of which have significant implications on antiviral regimen choice. Confirmatory sequencing of ambiguous results is crucial for accurate genotyping.

Short article: Viral dynamics among hepatitis C virus chronic infected patients during direct-acting antiviral agents therapy: impact for monitoring and optimizing treatment duration.

Direct-acting antiviral agents (DAAs) have provided an ultimate treatment duration of 12 weeks for most hepatitis C virus (HCV)-infected patients. The opportunity to reduce treatment duration to 6 or 8 weeks is being evaluated. Here, the HCV viral dynamics at short times during HCV therapies and its implications for monitoring and optimizing treatment duration have been assessed. HCV chronic infected patients who began HCV therapy (March 2014 to June 2015) at a reference hospital of the Northwest of Spain were selected. HCV-RNA was quantified at different short time points during HCV therapy using Abbott RealTime HCV assay. Epidemiological, clinical, and virological data were recorded. Eleven HCV-infected patients were included; 90.9% had cirrhosis (>12.5 kPa) and 72.7% were treatment-experienced. HCV genotype 1b was the most prevalent (72.7%). All of the combinations were pegylated interferon-free and all included ribavirin. The median HCV-RNA (log IU/ml) at baseline was 5.8 (5.4-6.1); the decline between baseline and day 3, weeks 4, 8, and 12 was 3.2, 4.8, 5.1, and 5.6, respectively. Fewer than 50% of patients achieved undetectable viral load at weeks 4 and 8; however, all patients achieved a sustained virologic response at 12 weeks. Rapid and high HCV-RNA decline was observed among HCV-infected patients under DAA-based regimens, especially for those without cirrhosis. Despite low rates of patients with undetectable HCV-RNA at weeks 4 and 8, all achieved a sustained virologic response at 12 weeks. These findings suggest that the time points to monitor HCV-RNA during DAA therapies and the treatment duration need to be optimized.

Immiscible phase filter extraction and equivalent amplification of genotypes 1–6 of hepatitis C RNA: The building blocks for point-of-care diagnosis

The lack of hepatitis C virus (HCV) diagnostic tests designed for use in decentralized settings is a major obstacle for providing access to treatment and prevention services particularly in low and middle income countries. Here we describe the development and validation of two building blocks of the HCV Quant Assay, a test in development for point-of-care use: 1) an RT-qPCR assay with noncompetitive internal control that equivalently detects the 6 major HCV genotypes and 2) an automated sample prep method using immiscible phase filter technology. This novel assay has wide dynamic range of HCV quantification and a limit of detection of 30IU/ml with 200μl specimen volume. In a preliminary study of 61 clinical specimens, the HCV Quant Assay demonstrated 100% sensitivity and specificity and gave comparable viral load results across 4 logs of IU/ml when compared to the Abbott RealTime HCV Assay.

Clinical performance of the VERIS HCV assay for hepatitis C virus RNA quantification

BackgroundDiagnosis of hepatitis C virus (HCV) infection and treatment monitoring rely on detection/quantification of HCV RNA and real-time polymerase chain reaction (PCR) techniques are expected to equivalently quantify the different HCV genotypes. ObjectiveThe clinical performance of the VERIS HCV assay for HCV RNA quantification was compared to that of the Abbott RealTime HCV assay. Study designQualitative concordance and quantitative comparison were evaluated on a first panel of 286 clinical samples containing HCV genotypes 1–6. Forty additional genotype 4 samples were tested to explore genotype 4 HCV RNA underquantification. ResultsQualitative discrepancies were observed for low viral loads (<2 log10 IU/mL) in patients under antiviral therapy and would not have had any impact on patients’ management with the current guidelines for the monitoring of patients on direct-acting antivirals (DAAs). Quantification results were well correlated (R2=0.89) with an overall minimal quantification bias (mean VERIS − Abbott difference) of −0.09 log10 IU/mL. Quantification agreement for genotypes 1, 2 and 3 samples was excellent, but reached −0.57 log10 IU/mL for 46 genotype 4 samples. A lower quantification bias of −0.24 log10 IU/mL was observed when testing 40 additional genotype 4 samples with a second reagent lot. Underquantification was not associated with 5′ untranslated region (UTR) sequence polymorphisms but could be explained by 5′ UTR RNA molecular modeling. ConclusionHCV RNA quantification by the VERIS HCV assay and the Abbott RealTime HCV assay was well correlated for all HCV genotypes, except genotype 4 where 5′ UTR RNA folding may impact quantification. Nevertheless, this underestimation of HCV RNA levels had no impact on clinical use.

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

BackgroundThe 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. ObjectiveAptima’s analytical performance was compared to the Abbott RealTime HCV assay (RealTime) in a clinical routine setting. Study designOverall 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. ResultsInter-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. ConclusionsAptima 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.

Evaluation of the Xpert HCV Viral Load point-of-care assay from venepuncture-collected and finger-stick capillary whole-blood samples: a cohort study

Point-of-care hepatitis C virus (HCV) RNA testing offers an advantage over antibody testing (which only indicates previous exposure), enabling diagnosis of active infection in a single visit. In this study, we evaluated the performance of the Xpert HCV Viral Load assay with venepuncture and finger-stick capillary whole-blood samples. Plasma and finger-stick capillary whole-blood samples were collected from participants in an observational cohort enrolled at five sites in Australia (three drug and alcohol clinics, one homelessness service, and one needle and syringe programme). We compared the sensitivity and specificity of the Xpert HCV Viral Load test for HCV RNA detection by venepuncture and finger-stick collection with the Abbott RealTime HCV Viral Load assay (gold standard). Of 210 participants enrolled between Feb 8, 2016, and July 27, 2016, 150 participants had viral load testing results for the three assays tested. HCV RNA was detected in 45 (30% [95% CI 23-38]) of 150 participants based on Abbott RealTime. Sensitivity of the Xpert HCV Viral Load assay for HCV RNA detection in plasma collected by venepuncture was 100·0% (95% CI 92·0-100·0) and specificity was 99·1% (95% CI 94·9-100·0). Sensitivity of the Xpert HCV Viral Load assay for HCV RNA detection in samples collected by finger-stick was 95·5% (95% CI 84·5-99·4) and specificity was 98·1% (95% CI 93·4-99·8). No adverse events caused by the index test or the reference standard were observed. The Xpert HCV Viral Load test can detect active infection from a finger-stick sample, which represents an advance over antibody-based tests that only indicate past or previous exposure. National Health and Medical Research Council (Australia), Cepheid, South Eastern Sydney Local Health District (Australia), and Merck Sharp & Dohme (Australia).