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Hepatitis C virus (HCV) infection is one of the major global health problems, particularly for people who inject drugs (PWID). This study aimed to investigate the spontaneous clearance rate of HCV and associated factors with the clearance among PWID using an HCV core antigen (HCV-cAg) test. Blood samples were collected from 311 male PWID concentrated in a rehabilitation center in Haiphong,Vietnam, every 6 months for up to 18 months from 2007, and analyzed serologically and genetically. Of the 311, 240 (77.2%) were positive for anti-HCV antibody (HCV-Ab), and 219 (70.4%) for HCV-cAg,though three HCV-cAg positives were negative for HCV-Ab. Of the 219, 52.5% were co-infected with human immunodeficiency virus (HIV). The most prevalent HCV genotype was genotype 1 (45.7%),followed by genotypes 6 (40.6%), and 3 (7.6%). Spontaneous clearance of HCV-cAg was observed in 12 (5.5%) of 219 PWID during the observation period, and the clearance rate was 6.5 per 100 personyears (95% confidence interval, 3.5–11.3). HCV-cAg level was marginally higher in PWID co-infected with HIV than those without HIV (p = 0.054) and lower in PWID with HCV genotype 3 than those with other genotypes (p < 0.001). Only low HCV-cAg level at baseline was associated with HCV clearance (p < 0.001). HCV-cAg level correlated with the HCV-RNA load in plasma at baseline (Rho = 0.55, p

Background and Aim: Cirrhotic patients have lower response rates to DAAs with increased frequency of adverse events. This study aims to evaluate the value of HCVcAg as an early predictor of SVR to DAAs in cirrhotic patients to justify the treatment and avoid side effects. Patients and Methods: This prospective cohort study was conducted on 85 treatment-naive HCV cirrhotic patients who had fulfilled the inclusion and exclusion criteria of the National Treatment Protocol of chronic HCV infection. HCVcAg detection was done on 10th day of treatment. Predictivity of HCVcAg for SVR was assessed in terms of specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV) and accuracy rates. ROC curve was conducted to assess predictivity of HCVcAg as well. Results: SVR12 was (91.76%). HCVcAg was negative in 79 patients; 78 of them achieved SVR, while it was positive in 6 patients; all of whom did not achieve SVR. HCVcAg had sensitivity, specificity, PPV, NPV and accuracy rates of 100%, 98.73%, 85.71%, 100% and 98.82% respectively in prediction of SVR. With AUC of 0.929. There was a positive strong significant correlation between HCVcAg and SVR12 (r = 0.898, P = 0.015). Conclusion: HCVcAg is a sensitive, specific, accurate, easily available, and affordable on- treatment predictor of SVR in cirrhotic patients with chronic HCV with possible future treatment regimen modification to improve efficacy and tolerability in difficult to treat cirrhotic patients.

Graphical abstract Enzyme-linked immunosorbent assay (ELISA) is widely used for the detection of disease biomarkers. However, it utilizes time-consuming procedures and expensive instruments, making it infeasible for point-of-care (POC) analysis especially in resource-limited settings. In this work, a multicolorimetric ELISA biosensor integrated on a paper/polymer hybrid microfluidic device was developed for rapid visual detection of disease biomarkers at point of care, without using costly equipment. This multicolormetric ELISA platform was built on multiple distinct color variants resulted from the catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and the etching of gold nanorods (AuNRs). The vivid color changes could be easily distinguished by the naked eye, and their red mean values allowed quantitative biomarker detection, without using any sophisticated instruments. When this multicolorimetric ELISA was integrated on a paper/polymer hybrid analytical device, it not only provided integrated processing and high portability but also enabled fast assays in about 50 min due to the unique advantages of paper/polymer hybrid devices. The limit of detection of 9.1 ng/μL of the hepatitis C virus core antigen, a biomarker for hepatitis C, was achieved using this multicolorimetric ELISA platform. This multicolor ELISA analytical device provides a new versatile, user-friendly, affordable, and portable immunosensing platform with high potential for on-site detections of various viruses, proteins, and biomarkers for low-resource settings such as at home, public venues, rural areas, and developing nations. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03359-8.

Background Screening of blood donors in many countries is based on the use of serologic assays to detect specific anti-HCV antibodies (HCV Ab), but it lacks detection sensitivity. So, HCV RNA detection using the current gold standard real-time PCR is a must to rule out HCV infection with the main disadvantage being of high cost. HCV core antigen (HCV-c-Ag) immunoassay is proposed as a more cost efficient alternative to HCV RNA detection with PCR. Aim To evaluate the effectiveness of HCV-c-Ag detection as a cheap alternative to HCV RNA (PCR) in diagnosis of HCV infection in blood donors who are HCV Ab negative. Methods and results One hundred eighty-six volunteer blood donors who tested negative for HCV Ab were examined for HCV-c-Ag. Seven cases out of these 186 cases were HCV-c-Ag positive (4%). HCV RNA detection (PCR technique) was done to 30 cases (seven cases who test positive for HCV-c-Ag and 23 cases who test negative). Six out of the seven cases who were HCV-c-Ag positive (86%) were HCV RNA positive. Twenty-two cases out of the 23 cases who were HCV-c-Ag negative (96%) were HCV RNA negative. Conclusion HCV-c-Ag detection is an efficient method for diagnosis of HCV infection during screening of blood donors with high specificity (95.6%) and high negative predictive value (95.6%).

Background: Affordable and effective diagnostic and treatment monitoring algorithms are urgently needed to achieve the global elimination of hepatitis C virus (HCV) infection. Methods: A total of 274 patients were treated with direct-acting antivirals (DAAs) in the Spanish Hospital of Albacete between 2004 and 2020. This study compared the enzyme-immunoassay technique for HCV core antigen (HCVcAg) with the determination of RNA of HCV (HCV RNA) by polymerase chain reaction (PCR) in monitoring treatment with DAA, setting the lower limit of detection of HCVcAg < 3 fmol/L and RNA < 10 IU/mL. In all cases, the P value of differences associated with the contrast test was less than or equal to 0.05. Results: We evaluated the viral loads of our patients before treatment, during their treatment, and after its completion. The HCV RNA quantification at diagnosis was 2309327 IU/mL. The mean HCVcAg load was 5972 fmol/L. There was a strong correlation between HCVcAg levels and RNA levels with a Spearman rho of 0.832 (P < 0.01). The HCVcAg sensitivity at diagnosis was 99%, but the specificity could not be calculated because there were no true negatives or false positives at this point. Twelve weeks after treatment, in patients with treatment failure, we obtained a mean of 19084 IU/mL for RNA, while for HCVcAg, the mean was 103 fmol/L. At this time point, we also found a strong correlation between HCVcAg levels and HCV RNA levels with a Spearman rho of 0.775 (P < 0.01). Finally, the virological cure was achieved in 99% of our patients. The results for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100%, 99.87%, 86.33%, and 100%, respectively. Conclusions: HCVcAg determination is an excellent alternative to HCV RNA in the assessment of treatment response. This is particularly relevant in lower- and middle-income countries and resource-limited settings where the high cost of labor, equipment, and reagents can prohibit molecular testing.

About 10 million people in China are infected with hepatitis C virus (HCV), with the seroprevalence of anti-HCV in the general population estimated at 0.6%. Delaying effective treatment of chronic hepatitis C (CHC) is associated with liver disease progression, cirrhosis, hepatocellular carcinoma, and liver-related mortality. The extrahepatic manifestations of CHC further add to the disease burden of patients. Managing CHC-related advanced liver diseases and systemic manifestations are costly for both the healthcare system and society. Loss of work productivity due to reduced well-being and quality of life in CHC patients further compounds the economic burden of the disease. Traditionally, pegylated-interferon plus ribavirin (PR) was the standard of care. However, a substantial number of patients are ineligible for PR treatment, and only 40%-75% achieved sustained virologic response. Furthermore, PR is associated with impairment of patient-reported outcomes (PROs), high rates of adverse events, and poor adherence. With the advent of direct acting antivirals (DAAs), the treatment of CHC patients has been revolutionized. DAAs have broader eligible patient populations, higher efficacy, better PRO profiles, fewer adverse events, and better adherence rates, thereby making it possible to cure a large proportion of all CHC patients. This article aims to provide a comprehensive evaluation on the value of effective, curative hepatitis C treatment from the clinical, economic, societal, and patient experience perspectives, with a focus on recent data from China, supplemented with other Asian and international experiences where China data are not available.

An advanced and fully automated chemiluminescent enzyme immunoassay for the hepatitis C virus core antigen (HCVcAg) was recently developed in Japan. We aimed to evaluate its clinical utility. The new Fujirebio assay (Lumipulse Presto HCVcAg [LP-Presto]) was compared with 2 conventional assays (Lumipulse Ortho HCVcAg [LP-Ortho] and Abbott's Architect HCVcAg). Basic assessments of LP-Presto (reproducibility, stability, range of quantitation, and specificity) were performed on 220 frozen sera (83 positive and 137 negative by LP-Ortho) and 206 fresh sera (all negative by LP-Ortho). Correlation analysis was performed and the rates of concordance for each assay were determined. Additionally, the frozen sera of 42 hyperimmunoglobulinemia patients, including 3 unmeasurable by LP-Ortho, were tested by LP-Presto. All the basic assessments of LP-Presto were consistent with the results of LP-Ortho and Architect. The concordance rate between LP-Presto and LP-Ortho for the 220 frozen sera was 99.5% (219/220), and that between LP-Presto and Architect was 99.1% (218/220). LP-Presto (HCVcAg cut-off value; 20 fmol/L) was fully consistent with LP-Ortho (100%), which found 343 sera negative for HCVcAg. All 42 hyperimmunoglobulinemic sera were measurable using LP-Presto. In conclusion, the performance of LP-Presto was rapid and reliable, and nonspecific test results due to hyperimmunoglobulinemia were reduced when LP-Presto was used. Therefore, LP-Presto is a high-quality HCVcAg assay that shows promising applications.

INTRODUCTION: We compared the hepatitis C virus (HCV) core antigen test with the HCV RNA assay to confirm anti-HCV results to determine whether the HCV core antigen test could be used as an alternative confirmatory test to the HCV RNA test. METHODS: Sera from 156 patients were analyzed for anti-HCV and HCV core antigen using a chemiluminescent microparticle immunoassay (Architect i2000SR) and for HCV RNA using the artus HCV RG RT-PCR Kit (QIAGEN) in a Rotor-Gene Q instrument. RESULTS: The diagnostic sensitivity, specificity, and positive and negative predictive values of the HCV core antigen assay compared to the HCV RNA test were 77.35%, 100%, 100%, and 89.38%, respectively. HCV core antigen levels showed a good correlation with those from HCV RNA quantification (r =0.872). However, 13 samples with a viral load of less than 4000 IU/mL were negative in the HCV core antigen assay. All gray-zone reactive samples were also RNA positive and were positive on repeat testing. CONCLUSIONS: The Architect HCV core antigen assay is highly specific and has an excellent positive predictive value. At the present level of sensitivity (77%), the study is still relevant in a low-income setting in which most of the HCV-positive patients would go undiagnosed, since HCV RNA testing is not available and/or not affordable. HCV core antigen testing can also help determine the true burden of infection in a population, considering the fact that almost 50% of the anti-HCV positive cases are negative for HCV RNA.

The major bottleneck in most developing countries to attain the WHO goal of eliminating hepatitis C as a public health threat by 2030 is the limited access to molecular testing and loss of infected patients to follow up. Many of the hepatitis C virus (HCV) infected patients fail to get the confirmatory HCV RNA test done after initial screening for anti-HCV antibody. The hepatitis C core antigen (HCVcAg) chemiluminescence-based assay which is newly introduced in the Indian health setup could prove to be a potential marker in the single-point screening and confirmation of HCV infection. This study was done to evaluate the performance of the HCVcAg assay for diagnosis and treatment monitoring of patients with HCV infection.In this retrospective study 208 archived plasma samples from 184 patients were retrieved and all three markers for the laboratory diagnosis of HCV infection, anti-HCV, HCV RNA and HCVcAg were performed in a single freeze thaw cycle. For a subset of patients (n ​= ​24), paired samples, baseline samples and samples collected at 12 weeks after completion of treatment (SVR12) were available.The sensitivity and specificity of the HCVcAg assay were 91.58% and 99.12% respectively with HCV RNA as the gold standard for the detection of active infection. There was a strong correlation between HCVcAg and HCV RNA (R ​= ​0.85, p ​ ​0•0001). Among the paired samples, the concordance between the HCVcAg and HCV RNA at baseline and at SVR12 was 95.8%.The HCVcAg assay showed a good correlation with the gold standard HCV RNA assay, especially in the case of treatment naïve patients. Thus, the use of HCVcAg assay as tool for testing and confirmation of HCV infection has the potential to increase the uptake of HCV testing.

Background and study aim: Hepatitis C virus (HCV) infection is a major public health problem worldwide. Blood donations screening achieved mainly by serological identification of HCV-Antibody (Ab), has largely reduced HCV transmission. HCV Core Antigen (CAg) tests have been introduced to supplement anti-HCV tests and HCV PCR analyses. CAg may be a useful screening test for identifying window phase of HCV infected patients whom are candidate for blood donations. The study aimed to evaluate diagnostic performance of HCV core antigen in comparison to HCV-RNA quantification and anti-HCV-Ab analyses in attendances of blood bank of Zagazig University hospitals. Patients and Methods: The study was performed on 92 participants attending the blood banks of Zagazig University Hospitals for blood donation between May 2015 to November 2017. The participants were classified into two groups; group A, which included 46 donors (32 males and 14 females) with negative HCV antibody and group B, which Included 46 patients (30 males and 16 females) with positive HCV antibody. Clinical assessment, HCV AB detection by ELISA, Prototype ELISA for HCV core antigen for presence of HCV core antigen and HCV RNA Quantitative were done for all participants. Results: No significant differences between both studied regarding sex and age. A high significant relation between HCV AB positivity and negativity as regard HCV PCR was found in both groups. A high significant relation between HCV core antigen positivity and negativity as regard HCV PCR. There was high significant relation between HCV core antigen positivity and HCV PCR in group A patients. There was a high significant relation between HCV core antigen positivity and HCV PCR in positive HCV antibody patients and statistically a high significant relation between HCV core antigen negativity and HCV PCR in group B patients. Conclusion: HCV core Ag can be identified by serological ELISA. This assay is cheap, easily performed, and compatible with HCV PCR. Its application may prevent the vast majority of HCV transmissions caused by the transfusion of window phase donations.

In the present study, the possibility of hepatitis C virus core antigen (HCVcoreAg) detection in buffer solution, using atomic force microscope chip (AFM-chip) with immobilized aptamers, has been demonstrated. The target protein was detected in 1mL of solution at concentrations from 10-10М to 10-13М. The registration of aptamer/antigen complexes on the chip surface was carried out by atomic force microscopy (AFM). The further mass-spectrometric (MS) identification of AFM-registered objects on the chip surface allowed reliable identification of HCVcoreAg target protein in the complexes. Aptamers, which were designed for therapeutic purposes, have been shown to be effective in HCVcoreAg detection as probe molecules.

Electrochemical paper-based analytical devices (ePADs) are useful analytical devices that serve as point-of-care testing (POCT) devices for various clinical biomarkers in view of their simplicity, portability, and low-cost format. However, multistep reagent manipulation usually restricts the performance of the device for end users. Herein, we developed a sequential ePAD for sequential immunosensing fluid delivery by integrating dual flow behaviors (fast-flow/delayed) within a single paper platform for the simultaneous detection of hepatitis B surface antigen (HBsAg) and hepatitis C core antigen (HCVcAg). In the present work, a fast-flow channel was used for the automated washing of unbound antigens, while a delayed channel was created to store a redox reagent for further electrochemical analysis with a single buffer loading (the analysis time can be completed within 500 s). Hence, the undesirable complex procedure of multi-step reagent manipulation is scarcely needed by the user. The detection limit of the proposed ePAD was as low as 18.2 pg mL−1 for HBsAg and 1.19 pg mL−1 for HCVcAg. In addition, this proposed ePAD was also proven to be effective in real clinical sera from patients to verify its biological applicability. The ePAD sensor shows high promise as an easy-to-use, portable, and extendable sensor for other multiplex biological assays.

The diagnosis of Hepatitis C virus (HCV) infection can be challenging due to its cost and a lack of access to centralized testing. There is an urgent need to develop simplified HCV testing algorithms. The aim of this study was to evaluate the performance characteristics of a Hepatitis C core antigen (HCVcAg) assay in a decentralized, resource-limited setting. This is a descriptive cross-sectional study from a highly endemic area of Karachi, Pakistan. Between October 2019 and July 2020, subjects aged 12 years and above who screened positive for HCV antibodies were simultaneously tested for HCV RNA (Xpert HCV Viral Load, GeneXpert® IV, Cepheid, France) and HCVcAg (ARCHITECT HCV Ag assay, Abbott® Diagnostics) to confirm active HCV infection. An Abbott ARCHITECT® i1000SR Immunoassay Analyser was installed at a local district hospital as a point-of-care (POC) facility for HCVcAg testing, while samples for HCV RNA were tested in a central lab. Two hundred individuals (mean age 46.4 ± 14.5 years, 71.5% females), who screened positive for HCV antibody, were included in the study. HCV RNA was detected in 128 (64.0%) while HCVcAg was reactive in 119 (59.5%) cases. Performance of the Immunoassay Analyser was excellent with a higher throughput and quicker readout value compared to the GeneXpert System. The sensitivity and specificity of HCVcAg (≥10 fmol/L) at HCV RNA thresholds of ≥12 was 99.1% (95% CI: 95–100%) and 87.6% (95%CI: 78.4–94%). A strong agreement was observed between the HCVcAg assay and HCV RNA. The ARCHITECT HCV Ag assay showed high sensitivity and specificity compared to HCV RNA in a decentralized, resource-limited setting. It can therefore be used as a confirmatory test in HCV elimination programs, particularly for low-income countries such as Pakistan.

We evaluated the utility of Architect core antigen assay® Abbott Diagnostics (HCVAg) for monitoring patients with HCV infection and compared to HCV-RNA quantification (Cobas Ampliprep TaqMan-Roche Diagnostics). Samples from 262 patients were studied. Mean baseline HCV RNA and HCVAg levels were similar for responders (6.2 log IU/mL and 3.4 log fmol/L) and non-responders (6.1 log IU/mL and 3.2 log fmol/L), respectively. Only 10 patients failed to achieve SVR12 and all were detected by both assays. To evaluate HCVAg quantification as a tool for the detection of failure to DAAs, we performed a retrospective study of 132 non-responder patients. Mean HCV RNA and HCVAg levels at the time of detection of therapeutic failure were 5.88±0.97 log IU/mL and 3.19±0.79 log fmol/L, respectively. HCVAg (>3 fmol/L) was detected in 130/132 patients (98.5%). HCVAg assay was useful for patient selection and for evaluating virological response to DAAs in the real world.

Background The hepatitis C virus (HCV) core antigen (HCVcAg) may be an alternative diagnostic method to HCV RNA especially in populations such as substance users, the homeless or in resource-limited settings. Aims To evaluate performance of HCVcAg test in patients with opioid use disorder (OUD) on methadone in order to document its performance characteristics in the target population and to ensure that its specificity remains consistent across different populations. Methods HCVcAg levels from 109 methadone-maintained patients were compared to HCV RNA levels. Results Mean age was 53.8±7.8years, 59.6% were male, 68.8% African American, and 44% HCV-infected. HCVcAg was detectable in 47 of 48 HCV-infected, and undetectable in all HCV RNA negative patients. The HCVcAg assay had sensitivity of 97.9% and specificity of 100%. Correlation with HCV RNA levels was excellent (r=0.88, 95% CI 0.76; 0.95, p Conclusion HCVcAg has excellent performance for the diagnosis of HCV infection in patients with OUD on methadone.

Background: Chronic hepatitis C is a major public health problem around the world. In monitoring treatment efficacy, although costly and labour-intensive methods of molecular biology are of...

Introduction and Aim:Hepatitis C virus screening using anti-HCV antibody is recommended for end-stage renal disease and chronic hemodialysis patients. Since the anti-HCV antibody test is not able to differentiate a concurrent infection from a resolved past one, a more reliable and cost-effective screening test is needed. Materials and Methods: Prospective study of end-stage renal disease and chronic hemodialysis patients from a hospital unit who were screened by anti-HCV antibody and total ARCHITECT® HCV antigen assay. Results: Cohen's κ test was run to determine if there was agreement between HCV Ribonucleic Acid and HCV core antigen assays on 7 individuals with positive anti-HCV antibody. The two tests had a perfect measurement agreement. Conclusions: HCV core antigen testing could be used as a sensitive method for HCV infection screening in this group of patients based on its accuracy, simplicity and low expense

HCV is a potential cause of viral hepatitis, which leads to blood-borne chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Anti-HCV antibody detection assays detect HCV infection after approximately 70 days. HCV core antigen can be detected much earlier than anti-HCV antibodies. However, it disappears soon after the appearance of anti-HCV antibodies. Thus, there is a need for a rapid assay for simultaneous detection of HCV core antigen and anti-HCV antibodies for early diagnosis of HCV infection. A rapid diagnostic assay (HCV Ag-Ab Combo) for simultaneous detection of HCV core antigen and anti-HCV antibodies for early diagnosis of HCV infection was developed. HCV Ag-Ab Combo was evaluated in order to determine its potential for detection of HCV infection earlier than anti-HCV antibody detection assays. We compared the sensitivity of the newly developed assay with anti-HCV antibody detection assays (ELISA [HCV Ab ELISA] and rapid test [HCV Ab Rapid]) and HCV core antigen/anti-HCV antibody detection ELISA (HCV Ag-Ab ELISA). This study included 11 samples that were found positive in HCV RNA detection and HCV Ag-Ab ELISA but negative in HCV antibody detection assays (HCV Ab ELISA and rapid), 10 samples that were found positive in HCV Ag-Ab ELISA and HCV Ab ELISA but negative in HCV Ab Rapid, 69 samples that were found positive in HCV Ag-Ab ELISA, HCV Ab ELISA, and HCV Ab Rapid, and 509 samples that were found negative in HCV Ag-Ab ELISA, HCV Ab ELISA, and HCV Ab Rapid. Three seroconversion panels, PHV 913, PHV 911 (M) and PHV904-00-1.0, and a HCV RNA genotype qualification panel (2400-0182) acquired from Seracare Life Sciences (USA) were also tested. HCV Ag-Ab Combo showed a combined sensitivity and specificity of 100% when tested with 90 samples that were positive for HCV by HCV Ag-Ab ELISA and 509 HCV-negative samples. Its positive predictive value (PPV) and negative predictive value (NPV) were found to be 100%. It detected HCV infection approximately 7 to 12 days earlier than the HCV Ab detection assays, and its performance was not affected when testing different genotypes of HCV. HCV Ag-Ab Combo did not detect HCV infection as early as HCV RNA or HCV Ag-Ab ELISA. HCV Ag-Ab Combo provided a significant improvement for the early detection of HCV infection during the preseroconversion phase when compared with anti-HCV antibody detection assays. It could be a useful screening assay, and an alternative to HCV RNA detection or HCV Ag-Ab ELISA when nucleic acid technologies cannot be implemented.

Background and purpose: Hepatitis C virus (HCV) core antigen is highly sensitive and specific in viremic HCV diagnosis. This study evaluated the cost-effectiveness of HCV core antigen (HCVcAg) in community-based screening for active HCV infection. Methods: Between 2017/07 and 2018/07, community-based screenings for active HCV infection with two-step (anti-HCV for screening and HCVRNA for diagnosis) and one-step processes (HCVcAg for screening and diagnosis) were conducted in two districts in Kaohsiung City. While HCVcAg test was positive at ≥3 fmol/L, the lowest level of HCV-RNA detection was 12 IU/mL. We analyzed the cost-effectiveness of two algorithms in identifying active HCV infection. Results: There were two large-scale screenings using the two-step process with a total of 2452 residents enrolled; while six hundred and forty-four residents participated in continuous small-scale screening with the one-step process. The prevalence of anti-HCV and positive HCVcAg was 3.4% and 2.8%. The viremic rate was 1.4% and 2.8% for two- and one-step processes (p

OZ Objective: It was aimed to investigate diagnostic value of hepatitis C virus (HCV) core antigen test in patients with positive or negative anti-HCV assay by comparing with HCV ribonucleic acid (RNA) assay. Materials and Methods: Serum samples obtained from 189 patients who were admitted to Necmettin Erbakan University Meram Faculty of Medicine between December 2010 and February 2012, and HCV RNA assay were carried out for various reasons. Two mL of samples were stored under suitable conditions and antiHCV, HCV core antigen and strip immunoblot assay [Commercial INNO LIA™ HCV Score (Innogenetics NV in Ghent, Belgium)] were performed. Genotyping was performed in the amplicons of the samples with positive HCV RNA test. Results: The diagnostic sensitivity specificity, negative predictive value and positive predictive value of HCV core antigen test were 96.2%, 100%, 97.3%, and 100%, respectively. Sixty-five serum samples were genotyped and their distribution were detected: Fiftynine samples were genotype 1b, 2-genotype 1a/1b, 1-genotype 3a, 1-genotype 4, 1-genotype 2a/2c, and 1 was genotype 1a. Conclusion: It was concluded that HCV core antigen assay is highly specific, sensitive, reliable, reproducible, and easy to perform. It may be applied as a supplemental and confirmatory test in anti-HCV assays in the diagnosis of HCV.

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Background and aim To observe the clinical value of hepatitis C virus (HCV) core antigen (HCcAg) levels in monitoring acute HCV infection in patients with spontaneous clearance (SC) or clearance induced by antiviral therapy. Methods Patients with iatrogenic HCV infection (n = 104) were enrolled at the Shengjing Hospital, China Medical University, between 5 February 2013 and 3 April 2013. All cases were diagnosed with acute HCV infection, enrolled within 90 days of infection, and followed for 12 to 16 weeks. Blood was collected every month. HCV RNA and HCcAg levels were detected. From week 16, patients without SC were treated with pegylated-interferon and the HCV RNA and HCcAg levels were observed monthly. Follow-up was 7.5 (5.0 to 10.4) months. The Spearman correlation analysis was performed to determine the correlation between HCV RNA and HCcAg. Logistic regression analysis was used to determine the association of baseline HCV RNA and HCcAg levels with SC. Results Ten patients (9.62%) showed SC, with a negative conversion time of 57 (14 to 143) days. During follow-up, HCV RNA and HCcAg expression levels were positively correlated for each patient (except on the sixth month), but the levels of HCV RNA and HCcAg were not associated with HCV infection SC. Conclusions HCcAg levels could be of value for monitoring the course early HCV infection, but could not predict SC of HCV infection.

Three types of chitosan (chitosan I (n=371–744), chitosan II (n=682–930), and chitosan III (n=868–1365)) as well as gold nanoparticles (10 nm diameter) were used to modify diamond paste for the design of new stochastic microsensors. Hepatitis C virus core antigen was used as model analyte to prove the stochastic behavior of the proposed microsensors. The microsensors cover a linear range of concentration between 40 fg/mL and 4 ng/mL. The highest sensitivity (1.38×105 s−1/mg/mL) and the lower limit of determination (40 fg/mL) were obtained for chitosan III based microsensor. The hepatitis C virus core antigen was assayed from whole blood samples with recoveries higher than 98.00 %.

Simplified, affordable tools to diagnose active hepatitis C virus (HCV) infection are needed to scale up treatment. This study evaluated the analytical performance of HCV core antigen (HCVcAg) detection in samples of plasma and dried venous blood spots (DBSs). Paired plasma and DBS samples were prepared from remnant diagnostic samples, and plasma HCV RNA and HCVcAg were quantified. Sensitivity and specificity for HCVcAg (>3 fmol/L) at two HCV RNA thresholds (≥15 and ≥3000 IU/mL) were calculated. Of 120 paired samples tested, 25 had nonquantifiable HCV RNA and 95 had quantifiable HCV RNA. The median HCV RNA level in plasma was 5.6 log10 IU/mL (interquartile range: 5.2 to 6.2). The median HCVcAg levels in plasma and DBS samples were 2.3 log10 fmol/L (interquartile range: 0.1 to 3.1) and 1.1 log10 fmol/L (interquartile range: 0.0 to 1.9), respectively. For diagnosing HCV RNA ≥3000 IU/mL, the sensitivity and specificity of HCVcAg in plasma were 97.7% (95% CI, 91%–100%) and 100% (95% CI, 87%–100%), respectively. The sensitivity and specificity of HCVcAg in DBS were 88.6% (95% CI, 80%–94%) and 97% (95% CI, 82%–100%), respectively. The data from this study demonstrate good sensitivity and specificity of HCVcAg in plasma at an HCV RNA threshold of ≥3000 IU/mL. The level of HCVcAg quantified in plasma was higher than that in DBS.

Background: Simple, affordable diagnostic tools are essential to facilitate global hepatitis C virus (HCV) elimination efforts. Objectives: This study evaluated the clinical performance of core antigen (HCVcAg) assay from plasma samples to monitor HCV treatment efficacy and HCV viral recurrence. Study design: Plasma samples from a study of response-guided pegylated-interferon/ribavirin therapy for people who inject drugs with chronic HCV genotype 2/3 infection were assessed for HCV RNA (AmpliPrep/COBAS Taqman assay, Roche) and HCVcAg (ARCHITECT HCV Ag, Abbott Diagnostics) during and after therapy. The sensitivity and specificity of the HCVcAg assay was compared to the HCV RNA assay (gold standard). Results: A total of 335 samples from 92 enrolled participants were assessed (mean 4 time-points per participant). At baseline, end of treatment response (ETR) and sustained virological response (SVR) visits, the sensitivity of the HCVcAg assay with quantifiable HCV RNA threshold was 94% (95% CI: 88%, 98%), 56% (21%, 86%) and 100%, respectively. The specificity was between 98 to 100% for all time-points assessed. HCVcAg accurately detected all six participants with viral recurrence, demonstrating 100% sensitivity and specificity. One participant with detectable (non-quantifiable) HCV RNA and non-reactive HCVcAg at SVR12 subsequently cleared HCV RNA at SVR24. Conclusions: HCVcAg demonstrated high sensitivity and specificity for detection of pre-treatment and post-treatment viraemia. This study indicates that confirmation of active HCV infection, including recurrent viraemia, by HCVcAg is possible. Reduced on-treatment sensitivity of HCVcAg may be a clinical advantage given the moves toward simplification of monitoring schedules. This study was funded by the Australian Government Department of Health and Ageing. The views expressed in this publication do not necessarily represent the position of the Australian Government. The Kirby Institute is affiliated with the Faculty of Medicine, University of New South Wales. The opinions expressed in this paper are those of the authors and do not necessarily represent that of Merck Sharp and Dohme. Support from Abbott Diagnostics for the supply of reagents is gratefully acknowledged. GD is supported by a National Health and Medical Research Council Practitioner Research Fellowships. JG is supported by a National Health and Medical Research Council Career Development Fellowship. BH is supported by a National Health and Medical Research Council Early Career Fellowship. The ARCHITECT HCV Ag kits for this study were kindly provided by Abbott.

Purpose: The aim of the present study was to evaluate the efficacy of hepatitis C virus [HCV] core Ag assay by comparing it with anti-HCV antibodies and PCR-based technology for measuring viral load in diagnosis of HCV. Study design: HCV core Ag by ELISA in serum, in the presence or absence of antiHCV antibodies was compared to HCV- RNA by PCR on total number of 100 subjects, divided into 3 groups; including 80 patients and 20 volunteers. Results: The sensitivity of the test was (72.5%) and the specificity was (86.6%). Also positive predictive value of the test was (78.3%) and negative predictive value was (82.5%). Conclusion: Core antigen detection by ELISA can be used as a reliable test for detection of vireamia in HCV infection.

Enzyme immunoassays for quantifying hepatitis C virus (HCV) core antigen (Ag) have been proposed as an alternative to HCV RNA detection. The present study aimed to investigate the early kinetics of serum HCVcAg and its usefulness in predicting virological responses. The clinical data of 135 patients with chronic hepatitis C treated with pegylated interferon alpha (PEG-IFN-α) and ribavirin was retrospectively collected. The patients were grouped according to their treatment outcomes as follows: sustained virological response (SVR), nonsustained virological response (N-SVR), and relapse. Higher HCVcAg and HCV RNA levels were observed in patients in the N-SVR group than in the other groups at baseline. HCVcAg better predicted rapid virological response (RVR) compared with HCV RNA and had a predictive value similar to that of HCV RNA for SVR and early virological response. In the relapse group, HCV RNA decreased to 0 after 48 weeks, whereas HCVcAg was still detectable, indicating that HCVcAg more sensitively predicted relapse in antiviral therapy than HCV RNA. For patients treated with PEG-INF-α and ribavirin, HCVcAg may more sensitively predict relapse than HCV RNA.

Hepatitis C virus infects over 15 million patients from India and 2.86 million from Brazil. Detection of anti-hepatitis C virus antibodies has limited sensitivity during acute phase: the pre-seroconversion window period. Hepatitis C virus-RNA detection techniques are used to overcome this shortfall, but are costly and unavailable widely in developing countries. Estimation of hepatitis C virus core-antigen, a protein with highly conserved sequence, by enzyme-immunoassays is an economic and simpler alternative to RNA detection. This study was conducted in Delhi, involving 300 acute and chronic liver disease patients, tested for anti-hepatitis C virus 3rd-generation ELISA, hepatitis C virus core-antigen-ELISA and hepatitis C virus-RNA reverse transcription-polymerase chain reaction. Among the acute patients, hepatitis C virus core-antigen assay could identify 13 out of 14 pre-seroconversion window period cases and 6 out of 8 seroconverted cases, with a pre-seroconversion window period sensitivity of 92.9% and specificity of 100%. In hepatitis C virus core-antigen-positive cases, the viral load was in the range of 4900 to 1.46 × 106 IU/mL, whereas in hepatitis C virus core-antigen-negative cases, the range of viral load was 100–4500 IU/mL. The cost of the hepatitis C virus core-antigen-ELISA was estimated around 3–4 times lesser than the in-house reverse transcription-polymerase chain reaction and 9–10 times lesser than the United States Food and Drug Administration approved reverse transcription-polymerase chain reaction. With a good sensitivity and specificity in the acute phase of infection, hepatitis C virus core-antigen-ELISA can thus be a useful alternative in the developing nations. Keywords: Hepatitis C, Diagnosis, Core antigen, HCVcAg

Background The study aimed to evaluate a fully automated chemiluminescent immunoassay and compared it with a quantitative RNA assay and anti-HCV assay to verify the utility of this automated Ag assay as an alternative method for hepatitis C diagnosis. Methods A total of 229 serum samples previously tested for anti-HCV concentrations by the Architect Anti-HCV assay, were selected for HCV RNA testing by real time RT-PCR kit (Shanghai ZJ Bio-Tec Co., Ltd) and 125 specimens were tested for HCV Ag by the Architect HCV core Antigen kit. Results The log10 HCVAg and HCV RNA concentrations were highly correlated [ r = 0.834); with HCV RNA as the comparator test, HCVAg had 100% specificity, 100% positive predictive value (PPV) and 94.8% sensitivity. We found 1 pg/mL of total HCV core Ag is equivalent to approximately 6607HCV RNA international units (IU)/mL. Receiver operator characteristic curve analysis showed that the area under the curve of HCV core Ag (0.989) was greater than HCV Ab (0.871). HCV Ag concentrations and RNA-to-Ag ratio of the groups for HCV RNA concentrations ≤105 and >105 IU/mL were both significantly different from each other ( P Conclusion The Architect HCV core Ag assay may be an alternative method for hepatitis C diagnosis, performed on the same analytical platform and sample as the anti-HCV assay, shortening the diagnostic window period, demonstrating good correlation with HCV RNA assay with high specificity and positive predictive value.