Improving Diagnosis of Hepatitis C Virus Infection Using Hepatitis C Core Antigen Testing in a Resource-Poor Setting

Abstract 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.

IgG1 and IgG4 antibodies against core and NS3 antigens of hepatitis C virus

Abstract INTRODUCTION: IgG subclasses involved in the immune response to hepatitis C virus (HCV) antigens have been rarely studied. We investigated the immune response mediated by IgG1 and IgG4 antibodies against the recombinant core and NS3 antigens in patients with chronic hepatitis C. METHODS: Sixty patients infected with HCV genotype 1 without antiviral treatment and 60 healthy subjects participated in the study. Serum levels of alanine aminotransferase, HCV viremia, and the presence of cryoglobulinemia and liver fibrosis were determined. We investigated the serum IgG1 and IgG4 antibodies against recombinant HCV core and NS3 non-structural protein antigens using amplified indirect ELISA. RESULTS: Anti-core and anti-NS3 IgG1 antibodies were detected in 33/60 (55%) and 46/60 (77%) patients, respectively, whereas only two healthy control samples reacted with an antigen (NS3). Anti-core IgG4 antibodies were not detected in either group, while 30/60 (50%) patients had anti-NS3 IgG4 antibodies. Even though there were higher levels of anti-NS3 IgG4 antibodies in patients with low viremia (< 8 × 105 IU/mL), IgG1 and IgG4 antibody levels did not correlate with ALT levels, the presence of cryoglobulinemia, or degree of hepatic fibrosis. High production of anti-core and anti-NS3 IgG1 antibodies was observed in chronic hepatitis C patients. In contrast, IgG4 antibodies seemed to only be produced against the NS3 non-structural antigen and appeared to be involved in viremia control. CONCLUSIONS: IgG1 antibodies against structural and non-structural antigens can be detected in chronic hepatitis C, while IgG4 antibodies seem to be selectively stimulated by non-structural HCV proteins, such as the NS3 antigen.

Correlation between hepatitis C viral load and hepatitis C Core antigenaemia among Egyptians

Hepatitis C virus [HCV] infection is widespread in Egypt. This study compared HCV RNA with HCVcAg for the detection and quantification of viraemia among a sample of Egyptians. Sera from 80 suspected HCV-positive individuals were tested simultaneously for HCV-RNA load using real-time polymerase chain reaction [PCR] and HCVcAg level using ELISA. Of the 80 samples, 25% were HCV-RNA-negative. HCVcAg was detected in all samples: range 0.4-2462 ng/mL, mean 460 [SD 506] ng/mL. The sensitivity and specificity of HCVcAg were 96.7% and 90.9%, respectively. There was a significant correlation between serum HCV-RNA and HCVcAg levels [r = 0.4, P < 0.0001]. HCV-RNA remains the gold standard for diagnosis of active HCV infection but HCVcAg can be used where PCR is not available

Early predictive efficacy of core antigen on antiviral outcomes in genotype 1 hepatitis C virus infected patients

Response-guided therapy is of limited use in developing countries because hepatitis C virus RNA detection by sensitive molecular methods is time- and labor-consuming and expen- sive. We evaluated early predictive efficacy of serum hepatitis C virus core antigen kinetics on sustained virologic response in patients with genotype 1 hepatitis C virus during pegylated interferon plus ribavirin treatment. For 478 patients recruited, hepatitis C virus RNAs were detected at baseline, and at weeks 4, 12, 24, 48, and 72 using Cobas TaqMan. Architect hepatitis C virus core antigen was performed at baseline, and weeks 4 and 12. Predictive values of hepatitis C virus core antigen on sustained virologic response were compared to hepatitis C virus RNA. In the first 12 weeks after treatment initiation the dynamic patterns of serum hepatitis C virus core antigen and hepatitis C virus RNA levels were similar in sustained virologic response, relapse, and null response patients groups. Although areas under the receiver operating characteristics curves of hepatitis C virus core antigen were lower than those of hepatitis C virus RNA at the same time points, modeling analysis showed that undetectable hepatitis C virus core antigen (rapid virological response based on hepatitis C virus core antigen) had similar positive predictive value on sustained virologic response to hepatitis C virus RNA at week 4 (90.4% vs 93.3%), and hepatitis C virus core antigen decrease greater than 1 log10 IU/mL (early virological response based on hepatitis C virus core antigen) had similar negative predictive value to hepatitis C virus RNA at week 12 (94.1% vs 95.Z%). Analysis on the validation group demonstrated a positive predictivevalue of 97.5% in rapid virological response based on hepatitis C virus core antigen and a negative predictive value of 100% in early virological response based on hepatitis C virus core antigen. In conclusion, hepatitis C virus core antigen is comparable to hepatitis C virus RNA in predicting sustained virologic response of chronic genotype 1 hepatitis C virus infected patients, and can be used to guide anti-hepatitis C virus treatment, especially in resource-limited areas.

Inflammatory response of endothelial cells to hepatitis C virus recombinant envelope glycoprotein 2 protein exposure

The hepatitis C virus (HCV) encodes approximately 10 different structural and non-structural proteins, including the envelope glycoprotein 2 (E2). HCV proteins, especially the envelope proteins, bind to cell receptors and can damage tissues. Endothelial inflammation is the most important determinant of fibrosis progression and, consequently, cirrhosis. The aim of this study was to evaluate and compare the inflammatory response of endothelial cells to two recombinant forms of the HCV E2 protein produced in different expression systems (Escherichia coli and Pichia pastoris). We observed the induction of cell death and the production of nitric oxide, hydrogen peroxide, interleukin-8 and vascular endothelial growth factor A in human umbilical vein endothelial cells (HUVECs) stimulated by the two recombinant E2 proteins. The E2-induced apoptosis of HUVECs was confirmed using the molecular marker PARP. The apoptosis rescue observed when the antioxidant N-acetylcysteine was used suggests that reactive oxygen species are involved in E2-induced apoptosis. We propose that these proteins are involved in the chronic inflammation caused by HCV.

Preparation and application of a novel HCV diagnostic antigen fused to streptavidin / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To prepare streptavidin-tagged hepatitis C virus (HCV) fusion protein and explore its application for the detection of antibody against HCV infection.</p><p><b>METHODS</b>A recombinant plasmid pET-11d-C44P-SA was constructed, which coding a novel HCV diagnostic antigens (C44P) and streptavidin (SA) fusion protein, and the fusion protein was generated with BL21 (DE3) E Coli and identified by Western Blot analysis. Then the fusion protein was purified through the Ni-NTA affinity chromatography and over 90% purity has been achieved. Anti-HCV ELISAs were developed when the fusion protein was used in the biotin-pre-coated microplate or ordinary microplate, and then the sensitivity and specificity of the ELISA were evaluated with confirmed human sera panels.</p><p><b>RESULTS</b>The fusion protein was expressed in high yields and purified successfully, the ELISA detection of anti-HCV with human sera panel indicated that its sensitivity and specificity is higher when SA-tagged HCV antigen (C44P-SA) coated in biotin-pre-coated microplate, compared to C44P or C44P-SA coated in ordinary microplate.</p><p><b>CONCLUSION</b>The sensitivity and specificity of anti-HCV ELISA can be improved when a novel HCV diagnostic antigen fused to SA combined with the biotin- pre-coated microplate. This study laid a foundation for improving the performance of HCV diagnostics.</p>

Detection of hepatitis C core antigen in intravenous drug addictions / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the status of detection of hepatitis C core antigen in intravenous drug addictions, and discuss the foreground of the hepatitis C core antigen ELISA test system.</p><p><b>METHODS</b>HCV core antigen, HCV RNA quantity, anti HCV-IgG, HBsAg were analysis in all the plasma samples taken from 93 cases of intravenous drug users.</p><p><b>RESULTS</b>The specialty and sensitivity of HCV core antigen in intravenous drug addictions 100% -54% separately. When HBsAg were positive, the sensitivity of HCV core antigen was 38%, while HBsAg negative, the sensitivity of HCV core antigen was 69% (P < 0.01).</p><p><b>CONCLUSION</b>The detections of HCV core antigen showed high specialty but low sensitivity in intravenous drug addictions. The positive rate has positive relation with HCV RNA virus logarithm quantity. Coinfection with HBV are the interfere factor of HCV core antigen detection. In screening experimentations, the detection of HCV core antigen in plasma may be applied as supplement method for anti-HCV-IgG. It can also be used to monitor viremia in HCV infection.</p>

Detection of core antigen of hepatitis virus C in patients infected with hepatitis virus C and B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To observe the effect of hepatitis virus B on the detection rate of core antigen of hepatitis virus C in sera of chronic hepatitis C patients.</p><p><b>METHOD</b>HCVcAg and HCV RNA in sera were detected in 88 patients with chronic hepatitis C and 62 patients co-infected with HCV and HBV. At the same time, HBV DNA and HBeAg in sera were detected in 62 patients infected with HCV and HBV. Then we analyzed the correlation between HCVcAg and HBeAg/HBV DNA. The detection rates of HCVcAg in 88 patients with chronic hepatitis C and 62 patients co-infected with HCV and HBV were 72.7% (64/88) and 38.7% (24/62), respectively (x2 = 17.358, P less than 0.01).</p><p><b>RESULTS</b>The detection rates of HCV RNA in 88 patients with chronic hepatitis C and 62 patients co-infected with HCV and HBV was 81.8% (72/88) and 53.2% (33/62)respectively (x2=20.110, P less than 0.01). In 62 patients infected with HCV and HBV, the detection rate of HCVcAg in HBeAg positive patients and HBeAg negative patients were 28.6% (12/42) and 60% (12/20), respectively (x2 = 7.547, P = 0.011). Moreover, the positive rates of HBV DNA in HBeAg positive patients and HBeAg negative patients were 42.9% (18/42) and 80% (16/20), respectively (P more than 0.05). The detection rates of HCVcAg in HBV DNA positive patients and HBV DNA negative patients were 39.1% (18/46) and 37.5% (6/16), respectively (x2 = 0.013, P = 0.908). Compared with the detection rates of HCVcAg in patients only infected with HCV, the detection rate of HCVcAg in HBeAg or HBV DNA negative patients infected with HCV and HBV were 60% (12/20) (x2 = 1.266, P = 0.261) and 37.5% (6/16) (x2 =7.635, P less than 0.01), respectively.</p><p><b>CONCLUSION</b>The detection rate of HCVcAg in patients infected with HCV and HBV is relatively low. The reason is possibly that HBeAg inhibits duplication of HCV and decreases the expression of HCVcAg.</p>

Evaluation of the dried blood spot (DBS) collection method as a tool for detection of HIV Ag/Ab, HBsAg, anti-HBs and anti-HCV in a Malaysian tertiary referral hospital

<p><b>INTRODUCTION</b>Dried blood spot (DBS) collection is an appealing alternative to whole blood or plasma sampling, as it has technical and economic advantages over the latter.</p><p><b>MATERIALS AND METHODS</b>A prospective cross-sectional study was conducted at a Malaysian tertiary referral hospital from November 2009 to March 2010. One hundred and fifty paired specimens of DBS and plasma were analysed by the standard assays for HIV Ag/Ab, HBsAg, anti-HBS and anti-HCV, separately (total 600 paired specimens). DBS sample titres were then compared to the results of plasma testing, which was used as the gold standard.</p><p><b>RESULTS</b>For the HIV Ag/Ab assay with a cut-off point of 0.35 Relative Light Units (RLUs), the sensitivity and specificity were both 100%. For the HBsAg assay, the sensitivity was 96.5% and the specificity was 97.8%, with a cut-off point of 1.72 RLUs. Sensitivity for the anti-HBs test was 74.2% and the specificity was 86.9%, using a cut-off point of 0.635 RLUs. For the anti-HCV assay, the sensitivity was 97.3% and the specificity was 100%, with a cut-off point of 0.10 RLUs.</p><p><b>CONCLUSION</b>DBS is an ideal choice to be used as a screening tool for the detection of HIV, Hepatitis B and Hepatitis C virus infections. However, different cut-off values need to be used for the validation of test positivity in DBS samples because the small amount of blood in the DBS specimens leads to lower assay titres.</p>

Preparation and properties of SiO2 tubes immobilized antibody for HCAg detection / 生物工程学报

In order to optimize the fabrication of SiO2 tubes immobilized with antibody for hepatitis C virus antigen (HCAg) detection, we formed the activated amino on the surface of SiO2 tubes by using the activation of aminosilane. Then we immobilized the hepatitis C virus (HCV) monoclonal antibody on the surface of SiO2 tubes by using glutaraldehyde as a chemical cross-linker, followed by detecting HCAg. Sequence tests showed that when the SiO2 tubes were treated in 10% (V/V) aminosilane solution and 3% (V/V) glutaraldehyde solution for 3 hours and 2 hours, respectively, the HCV monoclonal antibody had high immobilization efficiency and low nonspecificity, and the HCAg was detected to 1 ng/mL. This experiment can provide principle and experimental data for establishment of HCAg magnetic immunoassay system.

Detection of hepatitis C virus antigen in hemodialysis patients / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the utility of the HCV core antigen ELISA in the detection of HCV infection in hemodialysis patients and to compare with Anti-HCV antibodies 3rd generation ELISA.</p><p><b>METHODS</b>Two hundred fifty hemodialysis patients were included in the study. Anti-HCV antibodies and total HCVcAg was determined by ELISA kits. HCV RNA was determined using reverse transcriptase polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>Forty-three out of 250 (17.2%) patients were positive for anti-HCV antibodies and 18% were positive for HCVcAg. 13/250 (5.2%) were positive for HCVcAg but anti-HCV negative, All 13 were confirmed viremic by in-house nested RT-PCR leading to specificity of 100%. Viral load of (49258 +/- 28682) copies/ml were detected in HCVcAg positive cases was higher in comparison to (23938 +/- 10780) copies/ml in the anti-HCV positive group (P < 0.05). The viral load of 4 negative cases for HCVcAg assay but anti-HCV positive was 306 +/- 161 copies/ml which was significantly lower in comparison to HCVcAg positive group (P < 0.001).</p><p><b>CONCLUSION</b>Detection of total HCVcAg together with anti-HCV will be useful for patients undergoing hemodialysis who have a longer window period due to immunosuppressed state. HCVcAg was compatible for the HCV RNA in serum and total HCVcAg ELISA is both a cost-effective and a less labor-intensive alternative to PCR, enhancing its clinical utility.</p>

Evaluation of the total hepatitis C virus core antigen assay in determining viraemia in Egyptian patients with chronic hepatitis C

Hepatitis C virus [HCV] is an important etiologic agent for chronic liver diseases in Egypt. Positivity of anti-HCV antibodies indicates past or current infection and in contrast to molecular detection of HCV-RNA does not give any indication about viral replication. Several problems still persist when RT-PCR is used for screening of patients. Recently, the availability of an anti-core antigen monoclonal antibody allowed development of an enzyme-linked immunosorbent assay [ELISA] detecting and quantifying total HCV core Ag [C-Ag] in peripheral blood of HCV-infected patients. The aim of this study is to evaluate the usefulness of the total HCV C-Ag in determining viremia compared to HCV-RNA detected by RT-PCR among anti-HCV positive Egyptian patients. In this study, 143 anti-HCV antibody positive patients were tested for HCV-RNA by PCR and HCV-Core antigen to evaluate the sensitivity and specificity of the latter. Among those 116 cases [81.11%] were HCV-RNA+ve and 111 [77.68] cases were HCV-Core Ag +ve, while 27 cases [18.84%] were HCV- RNA negative and 32[22.32%] were HCV-Core Ag -ve. Out of 116 patients who were HCV- RNA +ve, 111 [95.65%] were HCV-Core Ag +ve also, while 5 [4.35%] cases all with low viral load were negative. The sensitivity, specificity, PPV and NPV of HCV-Core Ag when referred to HCV-RNA were 95.7%, 100%, 100% and 84.4% respectively. Thus positive total HCV Core Ag could be a useful test in clinical practice to determine HCV viremia with a sensitivity and specificity close to that of PCR assays. However, a negative test is not reliable to exclude low viral load

Frequency of hepatitis-B and hepatitis-C in liver cirrhosis

To observe the frequency of hepatitis B and C in cases of liver cirrhosis. This descriptive study was conducted in all the Medical wards of Bahawal Victoria Hospital, Bahawalpur from June 2005 to May 2006. One hundred cases of liver cirrhosis presented through out patient or emergency department in the medicine department of Bahawal Victoria Hospital Bahawalpur who fulfilled the inclusion criteria were included in the study. Out of 100 patients, 59 [59%] were male and 41[41%] were female. Majority of the patients [80%] were 20 to 59 years old. HBsAg was positive in 28 [28%] patients, HCV RNA in 43 [43%], both HBsAg and HCV RNA were positive in 06 [06%] and negative in 23 [23%] cases. Most of the patients [46%] were in grade "B" of Modified Child Pugh's classifications, Among them 20 were HCV RNA positive and 15 HBsAg positive, While 20 [20%] were in grade "A" and 34 patients [34%] in grade "C". The risk factors for transmission of HBV and HCV infection were identified in 43% of cases. Chronic HCV is a leading cause of cirrhosis in Bahawalpur, followed by chronic HBV infection. Both the viruses in combination account for about three fourth of the total cirrhotics

Changing frequency of hepatitis-B and hepatitis-C positive cases among blood donors screened in blood bank at Nishtar hospital, Multan

To determine the change in frequency of Hepatitis-C and B in blood donors presented for screening at blood bank of Nishtar Hospital, Multan. This cross sectional, descriptive hospital based study was carried out in Community Medicine Department, Nishtar Medical College, Multan in collaboration with the Blood Bank at Nishtar Hospital, Multan. A total of 300 donors were screened for hepatitis-B and hepatitis-C during the month of June 2009. Among 300 blood donors screened for hepatitis-B and hepatitis-C, 92.7% were males while females were only 7.3%. Among all blood donors screened, 6% were found hepatitis-B positive and 5.3% were found hepatitis-C positive. Hepatitis-B and hepatitis-C are increasing at an alarming rate in Multan and the surrounding areas. Aggressive measures are needed for control this epidemic

Establishment of a tight tetracycline-controlled HCV-C double transgenic mouse model / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop a tight tetracycline-controlled HCV-C double transgenic mouse model.</p><p><b>METHODS</b>By crossbreeding of ApoE-rtTA-tTS transgenic mice with TRE-HCV-C transgenic mice, the double transgenic mice were produced in the F1 generation. The presence of HCV-C and tTS gene in the F1 generation was confirmed by PCR, followed by further identification and quantification of the transgene using Southern blot hybridization. The expression of HCV-C in the liver of the mouse model was detected immunohistochemically.</p><p><b>RESULTS AND CONCLUSION</b>Two transgenic mice were obtained, which contained ApoE-rtTA-tTS and TRE-HCV-C genes in the genome. Five founders contained HCV-C gene as confirmed by PCR and Southern blot hybridization. The tight tetracycline-controlled system may facilitate further study of HCV-C gene expression and gene therapy of hepatic cellular carcinoma.</p>

Significance of the hepatitis C virus (HCV) core antigen as an alternative plasma marker of active HCV infection.

PURPOSE: To evaluate the role of core antigen (Ortho trak-C assay) as a marker of active HCV infection in comparison to HCV RNA as detected by reverse transcription polymerase chain reaction (RT-PCR). METHODS: This evaluation was carried out during January 2000 to December 2003 in HCV infected individuals who were treatment naomicronve or were on anti-viral therapy. Additionally, sequential plasma samples from patients on clinical follow-up were included in this study. A total of 167 samples from 61 patients were tested by trak-C and RT-PCR. HCV RNA detection was achieved by a RT-PCR. Trak-C assay results were also compared in a limited proportion of these samples with known HCV viral load and genotype. RESULTS: Of 167 samples tested, 56.9% were RNA positive and 43.1% were RNA negative while 50.3% were trak-C positive and 49.7% were trak-C negative, yielding a sensitivity of 85.3% and a specificity of 95.8% for the trak-C assay (Kappa co-efficient = 0.8). The concentration of HCVcAg and HCV RNA showed significant correlation (n=38, r=0.334, P =0.04). The trak-C assay detected the most prevalent HCV genotypes in India without significant difference (P =0.335). The difference between mean absorbance values of HCV RNA positive samples compared to HCV RNA negative samples in the trak-C assay was highly significant (P < 0.000). Qualitative results of trak-C assay and RT-PCR were comparable in 93% of follow-up samples. CONCLUSIONS: Trak-C assay can be recommended for confirmation of HCV infection and follow-up in laboratories with resource-poor facilities.

Detection of serum anti-F antibody in hepatitis C virus infected patients / 中华流行病学杂志

<p><b>OBJECTIVE</b>To assess the prevalence of serum anti-F in patients with hepatitis C virus (HCV) infection and the distribution of anti-F.</p><p><b>METHODS</b>The recombinant protein (HCV-F/GST) was coated onto micro titer plates as antigen. Sera of 120 patients with hepatitis C virus infection, 15 patients with hepatitis B, 3 patients with hepatitis E and 10 normal sera were tested by indirect ELISA for detecting anti-F.</p><p><b>RESULTS</b>82 samples out of the 120 (68%) HCV infected patients exhibited a positive anti-F reaction, showing significant difference from the controls with no HCV infection (P < 0.01). Data from logistic analysis showed that the positive rate of anti-F was higher in patients over 50 year olds (OR = 6.675, 95% CI: 2.407-19.071). Patients of midrange, severe phase and hepatic cirrhosis had higher rate than the others (OR = 2.749, 95% CI: 1.470-5.141).</p><p><b>CONCLUSION</b>Prevalence and distribution of anti-F in Yixing hepatitis C patients was reported and which might be related to the progression of HCV infection.</p>

Evaluation on the use of detection of hepatitis C core antigen for screening blood donor / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the value of detection of hepatitis C virus core antigen (HCV-cAg) for screening blood donor by using the internal reagent enzyme immunoassay (EIA) and anti-HCV antibody.</p><p><b>METHODS</b>The first and repeat assays were performed for detection of serum anti-HCV and HCV-cAg ELISA in 3972 donor's serum specimens from August to October of 2004. Twenty-five donors positive for anti-HCV were tested with HCV-cAg EIA kits and the results were compared with the results of HCV RNA determination with RT-PCR method.</p><p><b>RESULTS</b>In 3972 donor's serum samples, only 1 serum specimen was positive for HCV RNA identification among 10 specimens which were positive for anti-HCV in first assays, and only 1 serum specimens was positive for HCV RNA identification among 12 specimens positive for anti-HCV in repeat assays, only 2 serum specimens were positive HCV RNA identification in 3 specimens which were positive for HCV-cAg assays.</p><p><b>CONCLUSION</b>The sensitivity of HCV-cAg ELISA is similar to HCV RT-PCR, but it is much cheaper. Therefore, HCV-cAg ELISA and anti-HCV may be used together to screen blood donor.</p>

Evaluation of the HCV core antigen assay as a second-line supplemental test for diagnosis of active hepatitis c infection

Hepatitis C virus core [HCV] antigen assays have been produced to exclude infectious donations collected the preseroconversion window phase. For the same purpose, we evaluated the specificity and sensitivity of a novel hepatitis C virus core antigen detection immunoassay and the applications of this assay in clinical diagnosis. Samples were collected from 30 anti-HCV antibody negative healthy subjects [Gi], and 46 anti-HCV antibody positive patients [G2]. All included samples were subjected to HCV core antigen and HCV-RNA PCR. Among the 46 anti-HCV Ab positive samples, HCV core antigen was positive in 38 samples from 40 samples positive for HCV-RNA with sensitivity of 95% [38/40]. All the 30 anti-HCV Ab negative samples [n=30] were negative for both HCV core antigen and HCV-RNA with specificity of 100% .There was no significant variation in the sensitivity of HCV core antigen between genotype 1 [100%] and genotype 4 [94.5%]. Viral load in HCV core antigen positive samples [906653 +/- 133803] was significantly increased than that of HCV core antigen negative samples [16342 +/- 5245] with P value<0.05. HCV core antigen assay is a useful method in screening strategy of HCV infection and provides a reliable means of distinguishing between current and cleared HCV infections that is well correlated with HCV-RNA testing