Anti-HCV IgG avidity index in acute hepatitis C

Coppola, Nicola; Pisapia, R.; Marrocco, Cecilia; Martini, Salvatore; Vatiero, Luisa Maria; Messina, Vito; Tonziello, Gilda; Sagnelli, Caterina; Filippini, Pietro; Piccinino, F

doi:10.1016/j.jcv.2007.07.005

Cited by 39 publications

(23 citation statements)

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“…16,19,23 Previous studies have found that patients with resolved HCV infection can have a lower avidity index compared to chronic patients whose antibodies are continually exposed to the HCV virus. [16][17][18][19] A testing algorithm has been developed for HCV avidity using either plasma or DBS. In our laboratory we found that two dilution factors were required to help differentiate between chronic and resolved infections when the sample had an AI < 30 and was PCR negative.…”

Section: Discussionmentioning

confidence: 99%

“…Several papers have addressed HCV avidity testing but all have been described using plasma/serum samples. [15][16][17][18][19] All the HCV avidity methods reported are modifications of commercial or in house ELISA kits using either guanidine or urea as the DA. The method described in this paper uses a modified commercial assay with an overnight incubation stage for HCV avidity testing.…”

Section: Introductionmentioning

confidence: 99%

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A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots

Shepherd

Kean

Hutchinson

et al. 2013

Journal of Clinical Virology

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This version is available at https://strathprints.strath.ac.uk/42887/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. a b s t r a c tBackground: DBS testing has been used successfully to detect HCV antibody positive individuals. Determining how long someone has been infected is important for surveillance initiatives. Antibody avidity is a method that can be used to calculate recency of infection. Objectives: A HCV avidity assay was evaluated for both plasma and DBS. Study design: To measure antibody avidity a commercial HCV ELISA was modified using 7 M urea. The plasma samples were split into: group 1 (recently infected N = 19), group 2 (chronic carrier N = 300) and group 3 (resolved infection N = 82). Mock DBS made from group 1 (N = 12), group 2 (N = 50), group 3 (N = 25) and two seroconverter panels were evaluated. 133 DBS taken from patients known to have a resolved infection or be a chronic carrier were also tested.Results: The avidity assay cut-off was set at AI ≤ 30 for a recent infection. Using sequential samples the assay could detect a recent infection in the first 4-5 months from the point of infection. Most of the false positive results (AI < 30 among cases known not to have had recent infection) were detected among known resolved infections, in both the plasma and DBS; as a result, a testing algorithm has been designed incorporating both PCR and two dilution factors. The sensitivity and specificity of the assay on plasma was 100% and 99.3%, respectively, while DBS had 100% sensitivity and 98.3% specificity. Conclusion:The HCV avidity assay can be used to distinguish between chronic and recent infection using either plasma or DBS as the sample type.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots

Shepherd

Kean

Hutchinson

et al. 2013

Journal of Clinical Virology

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“…Such assays perform very well when analysing seroconversion panels [16,17], providing clear cut-off AI values which distinguish samples taken within 20-100 days of infection from those derived from patients with chronic infection. Importantly, samples from chronically infected patients with acute exacerbations have high avidity (as would be expected), increasing the specificity of this approach [17]. However, there is no current standardised agreed methodology for these assaysreports differ in terms of which chaotropic agent is used (e.g.…”

Section: F I G U R E 1 the Natural History Of Hcv Infectionmentioning

confidence: 99%

Acute hepatitis C virus infection

et al. 2008

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Around 25% of people infected with hepatitis C virus (HCV) are able to clear the infection spontaneously, while the majority become chronically infected, with a subsequent risk for the individual patient of progressive inflammatory liver disease, cirrhosis, hepatocellular carcinoma and liver-related death (Figure 1). Much is known about the epidemiology, pathogenesis, diagnosis and management of chronic HCV infection. In comparison, knowledge about acute HCV infection is patchy. In this article, we will highlight concerns relating to acute HCV infection and suggest that public health bodies responsible for managing the HCV epidemic should redirect at least some of their resources to dealing with these issues.

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“…Commercial immunoassays for anti-HCV antibody detection have been adapted to test for avidity. They have confirmed that anti-HCV avidity increases with time after primary infection (3,11,17). However, the limited evaluation of such assays in small populations has hampered their development for use in clinical practice.…”

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confidence: 96%

Use of an Anti-Hepatitis C Virus (HCV) IgG Avidity Assay To Identify Recent HCV Infection

et al. 2010

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There is no reliable and simple diagnostic marker available to diagnose recent hepatitis C virus (HCV) infection. It has been shown that the avidity of specific IgG antibody is low in primary viral infection and increases with time. We report the development of an anti-HCV avidity assay derived from a commercially available test. A panel of 117 sera was first examined for IgG avidity. It was composed of samples from patients with recent (group 1, n ‫؍‬ 14), chronic (group 2, n ‫؍‬ 70), and resolved (group 3, n ‫؍‬ 33) HCV infections. Avidity index (AI) values observed in recently infected patients were significantly lower (12.0% ؎ 9.2% [mean ؎ standard deviation]) than those found in chronic carriers (83.1% ؎ 15.2%). Using a threshold of 43.0%, this assay distinguished between groups 1 and 2 with very high sensitivity (98%) and specificity (100%). For group 3, a broader distribution of the AI values was observed (54.8% ؎ 27.3%), suggesting that this index would not be useful in HCV RNA-negative patients. Blind validation of the test was carried out with a panel of 36 serum samples from 17 HCV seroconverters. The assay described here is a useful tool to distinguish recent from chronic infection in HCV-viremic patients.

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Anti-HCV IgG avidity index in acute hepatitis C

Cited by 39 publications

References 28 publications

A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots

A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots

Acute hepatitis C virus infection

Use of an Anti-Hepatitis C Virus (HCV) IgG Avidity Assay To Identify Recent HCV Infection

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