The diagnostic significance of an assay for ‘total’ hepatitis C core antigen

Kurtz, J. B.; Boxall, Elizabeth; Qusir, N.; Shirley, Jane A.; Coleman, Diana Lewis; Chandler, C.

doi:10.1016/s0166-0934(01)00327-5

Cited by 21 publications

(15 citation statements)

References 4 publications

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“…Also, while our study population consisted exclusively of treatmentnaïve patients, the studies of Veillon et al (36) and BouvierAlias et al (6) included patients undergoing therapy. Not only do the mean values for HCV core antigen and HCV RNA levels differ between these patient groups, but the relationship between HCV core antigen and HCV RNA concentrations may also vary between patients (6,16). For all of these reasons, the reported correlations between the concentration of HCV core antigen and the HCV RNA concentration may vary from study to study.…”

Section: Discussionmentioning

confidence: 98%

“…To our knowledge, ours is the first study to evaluate OTCA as a supplemental test in the diagnostic setting once seroconversion has been confirmed. Previous studies have evaluated the utility of OTCA for the screening of blood products, focusing on its potential to shorten the time to the identification of active infection prior to antibody production during the window period (12,16,17). Other studies have examined the assay's utility in the monitoring of therapy, as assessed by its ability to assess the presence or the absence HCV core antigen at a given time point or to examine the kinetics of HCV core antigen decline (22,32,36,37).…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of the Core Antigen Assay as a Second-Line Supplemental Test for Diagnosis of Active Hepatitis C Virus Infection

et al. 2004

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The British Columbia Center for Disease Control laboratory performs approximately 95% of all hepatitis C virus (HCV) antibody tests for the province's 4 million inhabitants. In 2002, the laboratory tested 96,000 specimens for anti-HCV antibodies, of which 4,800 (5%) were seroreactive and required confirmation of active infection. Although HCV RNA assays with a sensitivity of 50 IU/ml or less are recommended for the confirmation of active HCV infection, given the large number of seroreactive specimens tested annually, we evaluated the Ortho trak-C assay (OTCA) as a second-line confirmatory test and determined its limit of detection (LoD). Of 502 specimens from treatment-naïve anti-HCV-positive individuals, 478 had sufficient volumes for evaluation by the OTCA and HCV RNA tests. Core antigen was not detected in 147 of 478 (30.8%) of these specimens, of which 37 of 147 (25.2%) were shown to be viremic by the VERSANT HCV (version 3.0) (branched-DNA) assay and/or the VERSANT HCV qualitative assay. Testing of 144 replicates of a World Health Organization standard dilution series indicated that the LoD of OTCA was ϳ27,000 IU/ml. This LoD is consistent with the inability of OTCA to detect core antigen in clinical specimens with low viral loads. We conclude that OTCA has limited value as a confirmatory test for the diagnosis of active HCV infection because 37 of 367 (10%) of viremic specimens had undetectable core antigen. Qualitative HCV RNA testing remains the present standard for the confirmation of active HCV infection in the diagnostic setting.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Evaluation of the Core Antigen Assay as a Second-Line Supplemental Test for Diagnosis of Active Hepatitis C Virus Infection

et al. 2004

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“…This finding suggests that the assay might function as a confirmatory test when the presence of antibodies against HCV has been detected. When analyzing the sera from 145 HCV-negative blood donors, Kurtz et al suggested that a cutoff of 200 pg/ml might be appropriate (10). However, this value was based on an earlier version of the core antigen assay that has since been replaced.…”

Section: Discussionmentioning

confidence: 99%

“…Given these diverse effects, quantification of the HCV core protein might potentially be a better correlate of fibrosis progression than HCV RNA levels. Recently, a new enzyme immunoassay (EIA) for HCV core antigen has been developed (1) and has been proposed as a complement to standard HCV viral load quantification based on reverse transcription (RT)-PCR and branched-DNA analysis (10,23). In this study, our aim was to evaluate the possible association between core antigen and HCV RNA quantification with regards to the change in liver histology over time in untreated HCV-infected patients as well as to study the effect of duration of storage on sample integrity.…”

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confidence: 99%

Comparison of Serum Hepatitis C Virus RNA and Core Antigen Concentrations and Determination of Whether Levels Are Associated with Liver Histology or Affected by Specimen Storage Time

Lagging

Garcia²,

Westin

et al. 2002

J Clin Microbiol

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An enzyme immunoassay has recently been developed for the hepatitis C virus (HCV) core antigen. To evaluate the possible association between core antigen and HCV RNA levels with regards to the change in liver histology over time as well as study the effect of duration of storage on viral load results, sequential sera were analyzed from 45 patients with chronic HCV infection who had undergone two or more liver biopsies. A relatively strong association was found between the core antigen and HCV RNA concentrations (r s ‫؍‬ 0.8), with a core antigen level of 1 pg/ml corresponding to approximately 1,000 IU/ml. All 42 sera with detectable HCV RNA at the time of the second biopsy had core antigen concentrations above 1 pg/ml, and the three sera without detectable HCV RNA had concentrations below 1 pg/ml. No association was found between HCV RNA or core antigen levels and the stage of fibrosis in biopsy samples, progression of fibrosis, necro-inflammatory grade, steatosis, genotype, alanine aminotransferase level, or alcohol consumption. A significant association was demonstrated between the storage time of the samples and both the HCV RNA and core antigen concentrations. The median log HCV RNA concentrations (international units/milliliter) were 3.92 for the sera obtained at the time of the first biopsy (median storage time, 13.0 years) and 4.41 for the sera obtained at the time of the second biopsy (median storage time, 6.6 years) compared to 5.96, the median for 102 different routine clinical patient samples.

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“…Both assays are also expensive. An assay prototype designed to detect and quantify total HCV nucleocapsid core antigen (HCV core Ag) in serum and plasma in the presence or absence of anti-HCV antibodies has been recently developed (1,3,24). The HCV core Ag test is an enzyme-linked immunosorbent assay (ELISA) that can be performed in routine diagnostic laboratories.…”

mentioning

confidence: 99%

Novel Assay Using Total Hepatitis C Virus (HCV) Core Antigen quantification for Diagnosis of HCV Infection in Dialysis Patients

Fabrizi¹,

Lunghi

Aucella

et al. 2005

J Clin Microbiol

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Dialysis patients remain a high-risk group for hepatitis C virus (HCV) infection. The current diagnosis of HCV infection among dialysis patients includes serological assays and nucleic acid amplification technology (NAT) for assessing serum anti-HCV antibody and HCV viremia, respectively. However, current NAT techniques are expensive and labor-intensive and often lack standardization. An assay prototype designed to detect and quantify total HCV core antigen (total HCV core Ag) protein in serum and plasma in the presence or absence of anti-HCV antibodies has been recently developed. A comparison between a total anti-HCV core Ag enzyme-linked immunosorbent assay (ELISA) and a quantitative HCV RNA assay based on reverse transcription-PCR (RT-PCR) (Amplicor HCV Monitor test) was performed using a large (n ‫؍‬ 305) cohort of ELISA HCV 3.0 HCV-negative and -positive patients on maintenance dialysis. The concentrations of HCV core Ag and HCV RNA levels (measured by RT-PCR) were significantly correlated (r ‫؍‬ 0.471, P ‫؍‬ 0.0001) over a wide range of HCV RNA levels and were maintained among different HCV genotypes (HCV genotype 1, r ‫؍‬ 0.862, P ‫؍‬ 0.0001; HCV genotype 2, r ‫؍‬ 0.691, P ‫؍‬ 0.0001). We estimated that 1 pg of total HCV core Ag per ml is equivalent to approximately 19.952 IU of HCV RNA per ml, even if the wide range in the ratio of core Ag to HCV RNA (95% confidence intervals, 2.8 ؋ 10 3 to 1.6 ؋ 10 5 IU/ml) precluded definitive conclusions. In summary, total HCV core Ag proved to be useful for performing HCV RNA measurement among dialysis patients in routine laboratories without the need for special equipment or training. The present study supports the use of the total anti-HCV core Ag ELISA for assessing viral load among dialysis patients with HCV infection.Dialysis patients remain a high-risk group for hepatitis C virus (HCV) infection (11). The Centers for Disease Control and Prevention, Atlanta, Ga., have recently included semiannual anti-HCV testing for anti-HCV-negative patients in their infection control practices for hemodialysis units (6, 7).Routine diagnosis of HCV is based on detection of anti-HCV antibody. However, due to the absence of an efficient in vitro culture system for HCV or assays capable of detecting viral antigens, direct detection of HCV has depended on nucleic acid amplification technology (NAT) techniques. Indeed, serological assays for detecting anti-HCV antibody cannot distinguish between patients with active infection and those who have cleared the virus (29). NAT tests are based on nucleic acid amplification (PCR and transcription-mediated amplification) (16, 37) or signal amplification (branched-chain DNA assay) and are currently used to detect viremia (2, 36). Recently both assay systems have become semiautomated. Several problems still persist with these methods; PCR requires considerable skill and has limited reproducibility, while the branched-chain DNA assay requires a long incubation period. Both assays are also expensive. An assay prototype designed to detect and ...

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The diagnostic significance of an assay for ‘total’ hepatitis C core antigen

Cited by 21 publications

References 4 publications

Evaluation of the Core Antigen Assay as a Second-Line Supplemental Test for Diagnosis of Active Hepatitis C Virus Infection

Evaluation of the Core Antigen Assay as a Second-Line Supplemental Test for Diagnosis of Active Hepatitis C Virus Infection

Comparison of Serum Hepatitis C Virus RNA and Core Antigen Concentrations and Determination of Whether Levels Are Associated with Liver Histology or Affected by Specimen Storage Time

Novel Assay Using Total Hepatitis C Virus (HCV) Core Antigen quantification for Diagnosis of HCV Infection in Dialysis Patients

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