HCV Ag Research Articles

Performance evaluation of the Abbott Alinity Hepatitis C antigen next assay in a US urban emergency department population

IntroductionHCV antibody assays have been used to screen for HCV, but confirmation of acute infection is dependent on RNA or core antigen testing. The aim of the study was to compare the performance of five HCV test methods, including RNA testing, on a US emergency department population. MethodsClinical performance metrics were calculated on 708 consenting Johns Hopkins Emergency Department patients who self-reported an increased risk for HCV infection. Detection times of antibody, antigen, and RNA testing were compared using 89 samples from commercially available seroconversion panels. Testing was performed on the Abbott Alinity HCV Ag Next (RUO), Roche Elecsys HCV Duo, Abbott ARCHITECT Anti-HCV, and Elecsys Anti-HCV II assays. RNA testing was performed on the Abbott m2000 system. ResultsOverall, 21 (3.0%) participants tested positive for HCV on at least one test, 11 (52.4%) had chronic, 1 (4.8%) had an acute, and 3 (14.3%) had resolved infections. The Alinity HCV Ag Next assay demonstrated 99.43% specificity when compared to RNA testing. The Alinity HCV Ag Next assay also detected 91.67% of the active infections compared to RNA testing, while the Elecsys HCV Duo Ag assay detected only 58.33%. The seroconversion panel testing demonstrated that the Alinity HCV Ag Next assay detects an infection within 0.8 days of an RNA result. ConclusionThe Alinity HCV Ag Next assay demonstrated excellent concordance to RNA testing in a US urban E.D. population. This data supports the utility of Alinity HCV Ag Next in diagnosis of active HCV infections.

Performance of HCV core antigen and PCR testing in a predominantly genotype 3 population.

Hepatitis C core antigen (HCVcAg) is becoming increasingly recognized as an alternative to molecular testing for the confirmation of chronic hepatitis C. However, there are limited data on the performance of this assay in a genotype 3 (GT3) predominant country like Pakistan. We conducted a study to evaluate the diagnostic performance of HCVcAg against the HCV polymerase chain reaction (PCR) molecular test. HCV antibody-positive patients requiring confirmatory testing were recruited from August to October 2018 at the Pakistan Kidney and Liver Institute and Research Center (PKLI&RC), Lahore, Pakistan. Patients with previously known diagnoses or treatment histories were excluded. The Abbott HCV Ag assay was used for HCVcAg testing. Results ≥3.00 fmol/L were considered positive for HCVcAg. The Abbott RealTime HCV assay was used for PCR testing with a lower detection limit of ≥12 IU/mL. We computed the sensitivity, specificity and correlation of HCVcAg against HCV PCR. A total of 394 patients were recruited. The median age of the patients was 42 years. Most participants were females (51.5%, n = 203), 30.7% (n = 121) had HTN, 10.4% DM (n = 41) and 5% had APRI ≥2. The overall sensitivity was 98.0% and the specificity was 98.6%. The lowest detection limit of cAg was an HCV RNA value of 4657 IU/mL. The levels of cAg were highly correlated with those of HCV RNA by Spearman's rank correlation test (r = 0.935, p < .001). HCVcAg represents a suitable alternative with high sensitivity and specificity compared with HCV PCR in the GT3-predominant population and can be incorporated into algorithms to improve linkage to care.

A-244 Performance Comparison of the Alinity i Hepatitis C Core Antigen Assay in Routine Laboratory Testing vs HCV RNA Testing

Abstract Background The elimination of Hepatitis C by 2030 is a goal established by the WHO and other country specific health organizations worldwide. This goal is enabled by the availability of effective treatment regimens. A recent surprise in the US has been the increase in HCV infections during the COVID 19 pandemic, which may be caused by increased needle sharing. HCV Antibody assays have been used to screen for HCV, but confirmation of acute infection is relegated in the current US guidelines to PCR which often takes multiple days and may result in a loss to follow up and treatment, especially in high prevalence populations. HCV Core Antigen is a new immunoassay on the Alinity i system. The aim of the study was to evaluate the precision, linearity, and sensitivity of this research use assay in a US-based population. Methods Alinity i assay HCV Ab is an automated chemiluminescent immunoassay built to measure total antibody to the virus. Similarly, the Alinity i HCV Core Ag is a research use only automated chemiluminescent immunoassay for detection of HCV Core antigen in human plasma and serum. Precision (repeatability, and reproducibility) was determined over 3 days (4–10 replicates/day) using control material consisting of a negative human plasma control, and positive controls made with recombinant core Ag in buffer. Linearity was evaluated by preparing 4 dilutions of a remnant specimen with detectable HCV RNA viral load. Clinical sensitivity was determined using 90 remnant specimens with positive HCV Ab results. Specimens were confirmed positive for Hepatitis C via HCV RNA quantitation using the Aptima HCV Quant Dx transcription-mediated amplification (TMA) assay on the Panther System. Correlation between the HCV Ag assay and TMA was evaluated using specimens submitted for either Hepatitis C infection screening and monitoring of known infection. Results The repeatability of the HCV Ag assay ranged between 3.7% and 11.1% CV depending on the sample S/CO level tested. Dilution recovery averaged 98.2% (range 90.2%–107.3%) and a plot of HCV Ag concentration vs dilution factor showed a correlation coefficient R = 0.998 The Hepatitis C core antigen assay had a correlation coefficient R = 0.92 with the TMA. The HCV assay demonstrated a clinical sensitivity of 96.7% vs TMA. Conclusion The performance characteristics of the Alinity i HCV Core Ag assay highlight an opportunity to speed time to treatment by reflexing on the same instrument from HCV Ab to Ag and confirming effectiveness of treatment.

Community-Based Screening for Hepatitis B and C Infectivity Using Two Quantitative Antigens to Identify Endemic Townships.

Screening and linkage to care are essential to achieve viral hepatitis elimination before 2030. The accurate identification of endemic areas is important for controlling diseases with geographic aggregation. Viral activity drives prognosis of chronic hepatitis B and hepatitis C virus infection. This screening was conducted in Chiayi County from 2018–2019. All residents aged 30 years or older were invited to participate in quantitative HBsAg (qHBsAg) and HCV Ag screening. Among the 4010 participants (male:female = 1630:2380), the prevalence of qHBsAg and HCV Ag was 9.9% (396/4010) and 4.1% (163/4010), respectively. High-prevalence townships were identified, three for qHBsAg > 15% and two for HCV Ag > 10%. The age-specific prevalence of qHBsAg was distributed in an inverse U-shape with a peak (16.0%, 68/424) for subjects in their 40 s; for HCV, prevalence increased with age. Concentrations of qHBsAg < 200 IU/mL were found in 54% (214/396) of carriers. The rate of oral antiviral treatment for HCV was 75.5% (114/151), with subjects younger than 75 years tending to undergo treatment (85.6% vs. 57.4%, p < 0.001). QHBsAg and HCV Ag core antigens can reflect the concentration of the viral load, which serves as a feasible screening tool. Using quantitative antigen screening for hepatitis B and C in community-based screening, two hyperendemic townships were identified from an endemic county.

Label-Free Real-Time Detection of HBsAg Using a QCM Immunosensor.

Hepatitis B virus surface antigen (HBsAg) is an important protein in both diagnosis and prevention of hepatitis B infection. In the current study, a piezoelectric immunosensor based on antibody-antigen interaction was designed to detect HBsAg. A quartz crystal microbalance system was employed to detect antibody-antigen interaction. At first, an oscillator was designed to measure the resonant frequency affected by the reactants using IC 74LVC1GX04. Antibody against HBsAg was immobilized on 10 MHz AT-cut quartz crystal. The surface modifications were monitored by atomic force microscopy (AFM) and contact angle measurements. Different concentrations of antibody were used for surface immobilization and the frequency shifts were assessed. The system stability was studied by evaluating the stability of the crystal and the immobilized antibody. The adsorption of antibody onto the crystal was analyzed using AFM and changes in the resonance frequency. Further, a direct immunoassay was performed with this immobilized antibody to identify HBsAg solutions at different concentrations. Finally, specific and non-specific responses were investigated using hepatitis B (HBsAg) and hepatitis C (HCV Ag) antigens, respectively. Antibodies against HBsAg were successfully immobilized on 10 MHz AT-cut quartz crystal. The stability tests of crystal immobilized with antibody and unimmobilized crystal revealed that both forms of crystals were stable. Theoretical and experimental frequency assays were compared. A decrease in the contact angle indicated the hydrophilicity of surface after modifications. AFM images illustrated a more uniform surface after antibody adsorption and the surface roughness (RMS) reduced from 1.13 to 0.99 nm. Changes in the frequency were detected after the physical adsorption of HBsAb on the designed chip. The standard curve of antigen revealed the frequency changes depend on concentration of antigen. Finally, the specificity test confirmed the specificity of the designed biosensor for the detection of HBsAg from HCV Ag. The quantization of immobilized antibody was characterized by the frequency shift of the QCM. The obtained results were compared with ELISA assay. The correlation coefficients of HBsAg dilution between QCM and ELISA was 0.9821. This study is a new step to meet the challenges regarding HBsAg detection. Physical adsorption used in this study was effective as the simplest immobilization method to design a QCM-based immunosensor for HBsAg detection. Facilitated, fast, and simple detection of HBsAg by an antibody-based QCM biosensor is our main objective.

Role of hepatitis C virus core antigen assay in hepatitis C care in developing country

BackgroundThe World Health Organization (WHO) aims to achieve global hepatitis C elimination by 2030, defined as diagnosis of 90% of infected individuals and treating 80% of them. Current guidelines for the screening and diagnosis of hepatitis C infection denote using a relatively cheap screen with anti-hepatitis C virus (HCV) antibody immunoassay, followed by the much costlier molecular test for HCV RNA levels using polymerase chain reaction (PCR) assay to confirm active HCV infection. Simplification of the HCV evaluation algorithm to reduce the number of required tests could considerably expand the provision of HCV treatment especially in a developing country. This study investigates the performance of hepatitis C Core Antigen (HCV Ag) test by comparing HCV Ag results versus the results obtained with HCV ribonucleic acid (RNA) PCR which is considered the gold standard for the diagnosis of HCV infection.ResultsAmong the 109 anti-HCV positive sera, 96 were positive for both HCV Ag (> 3 fmol/L) and HCV RNA (> 15 IU/mL); 8 were negative for both tests, while the remaining 5 were positive for HCV RNA only. Considering the HCV RNA as gold standard; the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of HCV Ag test were found to be 95.05%, 100%, 100%, and 61.54%, respectively. HCV genotype was performed for 59 patients. The most common HCV genotype was genotype 1 (72.9%). Genotype 2 (15.3%) and genotype 3 (11.9%) were detected in the others samples. A high level of correlation was seen between HCV RNA and HCV Ag (r = 0.958, p < 0.001). The correlation for the samples that were genotyped 1 was significant (r = 0.966, p < 0.001).ConclusionIn our study, it was found that there was strong correlation between HCV RNA levels and HCV Ag levels. So, it can be used for a one-step HCV antigen test to diagnose active HCV infection.

Hepatitis C virus core antigen as alternative diagnostic algorithm for active hepatitis C virus infection among haemodialysis population: Cost implications.

In Malaysia, majority anti-HCV positive haemodialysis patients do not undergo hepatitis C confirmation due to the high cost of HCV RNA. HCV Core Antigen might be a cost-effective diagnostic test to identify HD patients who have active HCV infection eligible for Direct Acting Anti-viral therapy. A cross-sectional study was conducted to assess the correlation between HCV Ag and HCV RNA and the cost implications of different diagnostic algorithms to diagnose active HCV infection using Anti-HCV, HCV Ag, and HCV RNA. Pre-dialysis blood was tested for both HCV Ag and HCV RNA. HCV Ag was tested with Abbott ARCHITECT HCV Ag test. Two-hundred twenty-seven haemodialysis patients were recruited from 20 centres with mean age of 57.68 ± 12.48 years, and male constitutes 56.8% (129) of the study population. HCV Ag correlated well with HCV RNA (Spearman test coefficient 0.943, p < .001) with sensitivity of 93.9%, specificity 99.3%, and the accuracy was 97.36%. Cost analysis indicated that a sequential test involving Anti-HCV antibody as initial screening, followed by HCV Ag on Anti-HCV positive and HCV RNA on HCV Ag negative cases translated to a modest cost-saving algorithm compared to standard diagnostic algorithm. HCV Ag correlated well with HCV RNA and can potentially be fused in an alternative diagnostic algorithm to generate cost savings methods to diagnose active HCV infection among haemodialysis patients. This alternative algorithm is especially relevant in low to middle-income countries such as Malaysia to optimize the use of the healthcare resource and gains in clinical outcomes.

Hepatitis C core antigen testing to diagnose active hepatitis C infection among haemodialysis patients

BackgroundHepatitis C virus (HCV) infects more than 71 million people worldwide and chronic HCV infection increases the risk of liver cirrhosis and failure. Haemodialysis (HD) is one of the renal replacement therapies with risk of HCV transmission. Anti-HCV antibodies are the serological screening test for HCV infection that does not detect active phase of infection. Majority HCV infected HD patients in Malaysia do not have further HCV RNA performed due to high cost and thus HCV treatment is less frequently offered. HCV Core Antigen (HCV Ag) can potentially be used to diagnose active HCV infection in HD population in comparison to HCV RNA, at lower cost.MethodsWe conducted a cross-sectional study to assess the correlation between HCV Ag and HCV RNA and to identify the prevalence of active HCV infection among HCV seropositive HD patients from dialysis centres across West Malaysia from July 2019 to May 2020. Pre-dialysis blood was taken and tested for both HCV Ag and HCV RNA tests. HCV Ag was tested with Abbott ARCHITECT HCV Ag test.ResultsWe recruited 112 seropositive HD patients from 17 centres with mean age of 54.04 ± 11.62 years, HD vintage of 14.1 ± 9.7 years, and male constitute 59.8% (67) of the study population. HCV Ag correlates well with HCV RNA (Spearman test coefficient 0.833, p < 0.001). The sensitivity was 90.7%, specificity 100%, positive predictive value (PPV) 100%, negative predictive value (NPV) 76.5%, and accuracy 92.9%. For HCV RNA level > 3000 IU/mL, HCV Ag had a higher sensitivity of 95.1% and greater correlation (Spearman test coefficient 0.897, p < 0.001). The prevalence of active HCV infection was 76.8% among HCV seropositive HD patients.ConclusionsAlthough HCV Ag is less sensitive, it shows an excellent correlation with HCV RNA and has 100% PPV. HCV Ag can be considered as an alternative diagnostic tool for chronic active HCV infection among HD cohort, who can then be considered for HCV treatment. For seropositive HD patient with negative HCV Ag, we recommend to follow-up with HCV RNA test.

Feasibility of anti-HCV reflex HCV Ag screening strategy in an HCV endemic community

The HCV core antigen (HCV Ag) assay displays high sensitivity and strong correlation with HCV RNA. However, the feasibility of anti-HCV reflex HCV Ag screening in a community-wide setting is rarely discussed. We performed a two-phase community-based hepatitis C screen in an HCV-prone area of central Taiwan. During the training phase, all participants were test for anti-HCV, HCV Ag and HCV RNA to validate sensitivity, specificity, and accuracy of HCV Ag. During the validation phase, an anti-HCV reflex HCV Ag screen was conducted based on the results of training phase. Outcomes of the study were presented as positive and negative predictive values (PPV and NPV). Of 935 training phase participants, the rate of positive anti-HCV and HCV Ag were 175 (18.7%) and 78 (8.3%), respectively. Test sensitivity, specificity, and accuracy of HCV Ag were 97.1%, 98.6%, and 97.8%, respectively. During validation phase, only anti-HCV-positive serum samples were tested for HCV Ag. Of 1932 participant, 285 (14.8%) were anti-HCV-positive. 133 (46.7%) of the 285 anti-HCV-positive samples were HCV Ag-positive. PPV and NPV were 98.4% and 99.3%, respectively. Across the entire participant sample, a significant linear correlation between HCV Ag and HCV RNA concentration was noted (r2=0.93, p-value<0.001) following log-log transformation. Anti-HCV reflex HCV Ag screening is a feasible strategy for aiding HCV-prone communities.

Hepatitis C virus antigen detection is an appropriate test for screening and early diagnosis of hepatitis C virus infection in at-risk populations and immunocompromised hosts.

Early diagnosis remains key for effective prevention and treatment. Unfortunately, current screening with anti-hepatitis C virus antibody (anti-HCV Ab) test may have limited utility in the diagnosis of HCV infection and reinfection. This is of special concern to at-risk population, such as immunocompromised hosts and end-stage renal failure patients on hemodialysis. HCV antigen (Ag) could be useful in identifying the ongoing infection in such clinical scenarios. Hence, we aimed to study the utility of HCV Ag testing for the diagnosis of acute and chronic hepatitis C. Of 89 samples studied, 19 were from acute hepatitis C patients who were immunocompromised or were on hemodialysis, 43 were from active chronic hepatitis C patients and 27 were from patients treated for chronic hepatitis C. All samples were tested for HCV Ag using the Abbott ARCHITECT HCV Ag assay. HCV Ag was reactive in 19/19 samples from acute hepatitis C patients and 42/43 samples from active chronic hepatitis C patients. It was nonreactive in all samples from treated patients. The test showed a sensitivity and specificity of 98.4% and 100.0%, respectively. The positive and negative predictive values were 100.0% and 96.4%, respectively. The HCV antigen test has high clinical sensitivity and specificity and is useful for the diagnosis of acute and chronic hepatitis C infection in at-risk and immunocompromised patients. Its short turnaround time and relatively low cost are advantageous for use in patients on hemodialysis and other at-risk patients who require monitoring of HCV infection and reinfection.

Clinical utility of hepatitis C virus core antigen assay in the monitoring of direct-acting antivirals for chronic hepatitis C.

BackgroundHepatitis C virus core antigen (HCV Ag) assay has been proposed as a more economical alternative to HCV RNA detection. This study aimed to investigate the clinical utility of HCV Ag assay in the monitoring of direct-acting antivirals (DAAs) for chronic hepatitis C patients.MethodsWe analyzed serum samples from 110 patients treated with paritaprevir/ritonavir, ombitasvir, and dasabuvir (PrOD) with or without ribavirin. The levels for both HCV Ag and HCV RNA assessed by COBAS TaqMan HCV (CTM) Test or Abbott RealTime HCV (ART) assay were evaluated at baseline, week 2, 4, and 12 during treatment and 12 weeks after completion.ResultsBaseline HCV Ag levels showed good correlations with HCV viral load (r = 0.879; p<0.001); whereas the correlation was slightly stronger with CTM test than with ART assay (p = 0.074). The concordance of HCV Ag and HCV RNA undetectability was significantly better in CTM test than in ART assay at week 2 (p = 0.003) and week 4 (p = 0.003). A sustained viral response 12 weeks off therapy (SVR12) was achieved in 108 patients (98%); the HCV Ag assay identified 99% of these patients. Both undetectability of serum HCV Ag and HCV RNA had high positive predictive value at week 2 (98% vs. 100%) and at week 4 (97% vs. 99%) in predicting SVR12.ConclusionsHCV Ag assay may be a feasible alternative to HCV RNA for the determination of SVR12 in patients treated with DAAs.

HCV core antigen is an alternative marker to HCV RNA for evaluating active HCV infection: implications for improved diagnostic option in an era of affordable DAAs.

The core antigen of the hepatitis C virus (HCV Ag) presents an alternative marker to HCV RNA when screening patients for HCV viremia. This study sought to evaluate the utility of HCV Ag as a marker to assess active HCV infection in individuals residing in an HCV-endemic area. From 298 HCV-seropositive individuals evaluated for the presence of anti-HCV antibody, HCV Ag and HCV RNA, anti-HCV antibody was detected in 252 individuals (signal-to-cutoff ratios ≥5), HCV RNA was detected in 222 individuals (88%), and HCV Ag was reactive (≥3 fmol/L) in 220 individuals (87%). HCV genotype 1, 3, and 6 were identified. HCV Ag significantly correlated with HCV RNA irrespective of HCV genotype and/or HBV co-infection (log HCV RNA = 2.67 + 0.95 [log HCV Ag], R2 = 0.890, p < 0.001). To predict HCV viremia (HCV Ag ≥ 3 fmol/L), the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 99%, 99%, 100%, 100% and 97%, respectively. We concluded that HCV Ag was a good surrogate marker for HCV RNA and could be used to diagnose active HCV infection in a resource-limited setting. As a result, a cost-effective strategy for screening and identifying active HCV carriers using HCV Ag detection would enable more patients access to efficacious and increasingly affordable direct-acting antivirals (DAAs) for the treatment of HCV infection.

P098 Evaluation of the performance of HCV AG in routine screening for hepatitis C in high-risk populations

IntroductionScreening high-risk populations for hepatitis C (HCV) using antibody (anti-HCV) does not immediately distinguish resolved and active infections and may miss acute infections. HCV core-antigen (HCVAg) screening has been introduced...

HCV antigen instead of RNA testing to diagnose acute HCV in patients treated in the Dutch Acute HCV in HIV Study.

Introduction: Affordable and sensitive screening methods for acute hepatitis C (HCV) are necessary to successfully intervene in the current HCV epidemic among HIV-positive men having sex with men. HCV core antigen (Ag) testing has been proven effective in diagnosing chronic HCV-infected patients at low costs. We studied the characteristics of HCV Ag testing in acute HCV-infected HIV-positive patients.Methods: Plasma samples were selected from acutely HCV genotype 1-infected patients treated with peginterferon, ribavirin and boceprevir in the Dutch Acute HCV in HIV Study. The control group consisted of HIV-positive patients with a newly raised alanine aminotransferase (ALT) (>41 U/L) in whom HCV RNA was undetectable and who were tested for HCV Ag. Spearman correlation coefficient between HCV RNA and HCV Ag was calculated together with the sensitivity and specificity of HCV Ag testing at acute HCV diagnosis.Results and discussion: Upon acute HCV diagnosis, HCV Ag was identified in 39 out of 44 patients with detectable HCV RNA levels. In all 23 control patients without detectable HCV RNA in plasma, HCV Ag was undetectable as well. This resulted in a sensitivity and specificity of HCV Ag of respectively 89% (95% CI 75–96) and 100% (95% CI 82–100). The correlation between HCV Ag and HCV RNA was 0.97 (p < 0.001) upon diagnosis.Conclusion: The data presented in this study suggest that HCV Ag testing is a sensitive and specific method that can be used in diagnosing AHCV in HIV-infected patients.

HCV Ag quantification as a one-step procedure in diagnosing chronic hepatitis C infection in Cameroon: the ANRS 12336 study.

Introduction: The diagnostic procedure for chronic hepatitis C infection (CHC) usually combines anti-HCV antibody (HCV-Ab) and HCV-RNA measurement. Quantifying HCV core antigen (cAg) as a one-step procedure could shorten the diagnostic process. We aimed to assess the performance of cAg quantification in diagnosing CHC and how it is influenced by concomitant HIV or HBV infections.Methods: The cAg was quantified by an automated assay (Abbott Diagnostics) in 465 HCV-Ab negative serum samples and 544 HCV-RNA positive serum samples (n = 1009) collected in patients from the Pasteur Center in Cameroon, some of whom were infected by HBV or HIV. Its performance was evaluated in comparison to the gold standard (ELISA or PCR) by estimating its sensitivity (Se) and specificity (Sp), and by comparing the area under ROC (AUROC) curves in each patient population: HCV mono-infected, HCV-HBV and HIV-HCV co-infected.Results: Among the 465 HCV-Ab negative patients, 51 and 79 were HIV- and HBV-infected, respectively, whereas among the 544 patients with CHC, 27 and 28 were HIV- and HBV-infected, respectively. The Spearman ρ correlation coefficient between cAg and HCV-RNA was 0.75 (p < 0.00001). The assay had a sensitivity of 95.7% (95% CI: 93.2–97.5) and a specificity of 99.7% (95% CI: 98.1–10) in diagnosing CHC, corresponding to an AUROC of 0.99 (95% CI: 0.98–1.0). Being HIV- or HBV-infected did not impact the performance of cAg (Se = 96.4%, Sp = 96.2% and AUROC = 0.98 (95% CI: 0.95–1.0) in the HBV group, Se = 100%, Sp = 88.2% and AUROC = 0.99 (95% CI: 0.97–1.0) in the HIV group, p between AUROC = 0.69).Conclusions: The cAg quantification displayed a high specificity and sensitivity for the diagnosis of CHC in Cameroon, and its performance was not significantly modified by a concomitant HIV or HBV infection. In the context of CHC elimination on a global scale, using cAg quantification as a screening tool to directly identify CHC could be a reliable tool in a “test and treat” strategy.

Hepatitis C virus core antigen assay: an alternative method for hepatitis C diagnosis.

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 < 0.05). 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.

The Utility of Automated HCV Core Antigen Assay as an Alternative to PCR in Chronic HCV Egyptian Patients

Hepatitis C is a disease with a significant global impact. Although the detection and quantitation of HCV RNA have been the standard method for the diagnosis and assessing individual patient response to the antiviral drug regimen, it is very sensitive testing, expensive, labor intensive, and requires technical skill. Since the HCV core Ag assay is easy to perform in an immunoassay format, cheap, and less prone to sample carryover contamination compared to nucleic acid tests, There is an increasing interest to use HCV core antigen as a reflex test for seropositive individual to identify the active HCV infection also can be used to detect the early HCV infection. Aim of the work: To compare the diagnostic accuracy of HCV core antigen with HCV-PCR in chronic HCV Egyptian patients. Patients and methods: HCV core Ag was measured by a fully automated chemiluminescent immunoassay (CLIA) ABBOTT diagnostics in 57 patients proven to be chronic hepatitis C from those 32 were treated with pegylated interferon and ribavirin therpay and achieved HCV RNA negative six monthes after stoppage of treatment ( successful SVR) and 25 chronic HCV patients not considered for treatment . Viral load was quantified with branched DNA (bDNA, Versant, Siemens) also sera were tested with the Architect HCV Ag test (Abbott Laboratories). Statistical analysis was performed on logarithmically transformed values. Results: HCV core antigen was detectable in 19/25 and grey zone in 4/25 HCV RNA positive sera while 2 sera were negative for HCV Ag. HCV-Ag was undetectable in all 32 HCV RNA negative samples. The sample with the lowest viral load that tested positive for HCV-Ag contained 1200 IU/mL HCV RNA. The levels of HCV core antigen showed a good correlation with those from the HCV RNA quantification (r = 0.907) HCV core Ag levels were correlated significantly with ALT levels (r = 0.516; P < 0.0001) Conclusion: In conclusion, the Architect HCV antigen assay is highly sensitive, (>90%) reliable, easy to perform, cost-effective, and applicable as a screening, supplemental, and preconfirmatory test for anti-HCV assays used in laboratory procedures for the diagnosis of hepatitis C virus infection.

Usefulness of a fourth generation ELISA assay for the reliable identification of HCV infection in HIV-positive adults from Gabon (Central Africa).

Background/ObjectivesGuidelines for optimized HCV screening are urgently required in Africa, especially for patients infected with HIV, who sometimes show false positive or false negative reactivity in anti-HCV antibody assays. Here, we assessed the usefulness of a fourth-generation HCV Ag-Ab ELISA for the identification of active HCV infection in HIV-positive patients.MethodsThis cross-sectional study was conducted between 03/2010 and 01/2013 and included 762 Gabonese HIV-positive adult patients. The results of ELISA (Monolisa HCV Ag-Ab ULTRA, Bio-Rad) were compared with those obtained by RT-PCR (gold standard). The optimal ELISA signal-to-cutoff (S/CO) ratio to identify patients with active hepatitis C (positive HCV RNA) was determined. Specimens were further tested by the INNO-LIA HCV Score assay (Innogenetics) and the Architect HCV Ag kit (Abbott) to define the best diagnostic strategy.ResultsSixty-seven patients tested positive for HCV (S/CO ratio ≥ 1) by ELISA. Of these, 47 (70.1%) tested positive for HCV RNA. The optimal S/CO associated with active HCV infection was 1.7. At this threshold, the sensitivity of ELISA was 97.9% (95% confidence interval (CI) 90.0–99.9%), its specificity was 91.3% (95% CI 85.0–95.5%), and HCV seroprevalence rate was 7.3% (56/762) (95% CI 5.6–9.4%). Among 57 HCV-seropositive patients with available INNO-LIA results, false reactivity was identified in 14 (24.6%), resolved HCV infection in two (3.5%), possible acute HCV infections in nine (15.8%) and likely chronic HCV infections in 32 (56.1%) patients. HCV core Ag was undetectable in 14/15 (93.3%) specimens that tested negative for HCV RNA whereas it was quantified in 34 (out of 39, 87.2%) samples that tested positive for HCV RNA.ConclusionsOur study provides comprehensive guidance for HCV testing in Gabon, and will help greatly clinicians to improve case definitions for both the notification and surveillance of HCV in patients co-infected with HIV.

Rib Shaft Tuberculous Granuloma an Osteolytic Malignant Mimic Lesion: A Case Report

SESSION TITLE: Infectious Disease Global Case Reports SESSION TYPE: Global Case Report PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM 02:30 PM INTRODUCTION: Chest wall involvement is a rare manifestation of tuberculosis.Globally, musculoskeletal tuberculosis (TB) occurs in 1-3% of patients with TB, while TB of the chest wall constitutes 1% to 5% of all cases of musculoskeletal TB.The risk of medical laboratory staff acquiring TB is 5 times more than non laboratory workers. CASE PRESENTATION: 36 year-old male was presented with back pain and non-painful swelling on the left side of the chest anterior over a period of 3 months. The medical history of this patient was unremarkable. He had no pulmonary symptoms, such as a productive cough, or other symptoms.General examination revealed that the patient was a febrile and well nourished.A large, firm, non-mobile, and non-tender mass in the left anterior thoracic wall , overlying skin appeared normal, with no wounds, scars, rash, or sinuses. no other swellings in the body, no lymph nodes enlargement. A plain radiograph of the chest revealed normal findings. CT showed : osteolytic lesion with swelling in the left 7Th rib anterior arc, suggesting malignancy. CT also shows destruction of the rib shaft with some depress of bone in the side of the soft tissue swelling with segment of about 2 cm break in the continuity of the rib. The white blood cell count was normal. All biochemical examinations as well as erythrocyte sedimentation rate were within normal ranges. A tuberculin test was positive 15 mm. HIV, HCV and HBS Ag tests were negative. CT guided fine needle aspiration was done and revealed small fragments of chronic granulomatous inflammatory tissue in a background of traumatic blood fragments of fibrocollagenous tissue contains some microgranulomas.There were composed of loose aggregates of epithelioid cells and dense aggregates of lymphocytes around. focal areas of early caseation necrosis.No evidence of neoplasia was seen.The patient is currently receiving daily antituberculous chemotherapy. DISCUSSION: The granulomatous inflammation of tuberculosis commonly affects the lungs and the hilar lymph nodes, rarely to affect the chest wall and rarer to cause TB granulomatous osteolytic mass in the rib shaft. Chondroma, osteochondroma, fibrous dysplasia, and lipoid granuloma are the common benign tumors involving the ribs while the malignant lesions are chondrosarcoma, myeloma multiplex and secondary deposits from the lung and breast. All these present as expansion of the rib at the affected site, lytic lesion or pathological fractures. Therefore, this case of osteolytic rib shaft mass with bone debris inside without pulmonary, pleural affection and moreover no central caseation or history of tuberculosis or toxemic manifestation make the case more mimic tumor in the rib.Radiologically, presence of an osteolytic lesion, widening of the rib with periosteal reaction and presence of sequestrum may indicate tuberculosis. A solitary rib involvement usually present and the most frequent location is the rib shaft (60%) (1) and this was evident in our case. In addition to history and a good clinical examination, uses of CT-scan and percutaneous needle biopsy CT guided, remain the gold standard for the diagnosis and that was followed in our case. However, Chang et al.(2) could confirm TB in all of their twelve cases only following rib resection, and opinionated that surgery is a final diagnostic and therapeutic option in parietal chest wall TB. FREE TO VIEW http://journal.publications.chestnet.org/article.aspx?articleID=1913027 1 of 2 5/12/2015 7:02 PM PDF created with pdfFactory trial version www.pdffactory.com Tuberculosis infections have been increasing in incidence during the last decades for a variety of reasons, including increasing numbers of patients with immunity-depressive diseases, drug resistance, aging population, and health care worker exposure (3). In the current case, the patient is medical laboratory technician for more than 14 years. He manipulated TB suspected samples. Also, absence of TB history in close contacts may increase the possibility of laboratory acquired infection CONCLUSIONS: The granulomatous inflammation of tuberculosis may mimic osteolytic lesion in ribs of the thoracic cage especially if early without radiologic evidence of caseation, this can occurs in immunocompetent. Reference #1: Chang JH, Kim SK, Lee WY. Diagnostic issues in tuberculosis of the ribs with a review of 12 urgically proven cases. Respirology 1999 Sep;4:249253. Reference #2: Faure E, Souilamas R, Riquet M, Chehab A, Le Pimpec-Barthes F, Manac’h D, Debesse B. Cold abscess of the chest wall: a surgical entity? Ann Thorac Surg 1998 Oct; 66:1174-1178. Reference #3: Watts HG, Lifeso RM: Current concepts review: tuberculosis of bones and joints. J Bone Joint Surg Am 1996, 78:288-98. DISCLOSURE: The following authors have nothing to disclose: Abdelbaset Saleh, Magda Ahmad, Nabil Awadalla No Product/Research Disclosure Information Copyright © 2015 American College of Chest Physicians http://journal.publications.chestnet.org/article.aspx?articleID=1913027 2 of 2 5/12/2015 7:02 PM PDF created with pdfFactory trial version www.pdffactory.com

Clinical utility of hepatitis C virus core antigen quantification in patients with chronic hepatitis C

BackgroundHepatitis C virus (HCV) core antigen has been proposed as a surrogate marker of HCV replication. HCV core antigen detection and quantification can thus theoretically be used instead of nucleic acid testing (NAT) to diagnose infection and manage antiviral therapy, with several advantages compared to HCV RNA assays. HCV core antigen can now be easily detected and quantified by means of a chemiluminescent microparticle immunoassay on the Abbott Architect device. ObjectiveThe aim of the present study was to evaluate the clinical performance of the Architect HCV Ag assay for the detection and quantification of HCV core antigen in patients with chronic HCV genotype 1–6 infections. ResultsThe Architect HCV Ag assay had a specificity of 100% (95%CI: 97.8–100%). HCV core antigen levels were not influenced by the HCV genotype. The lower limit of detection of 3fmol/L corresponded to approximately 1000IU/mL of HCV RNA, regardless of the real-time PCR assay used. HCV core antigen and HCV RNA levels correlated for HCV genotype 1–4 (r=0.89 and r=0.88 for the m2000 and the CAP/CTM v2.0 assay, respectively). ConclusionsThe Architect HCV Ag assay is highly specific and easy to perform. It represents a valuable screening, diagnostic and monitoring tool, especially in the era of new all-oral, interferon-free antiviral strategies that do not require high analytical sensitivity.