A hepatitis C virus core antigen assay is a cost-effective, sensitive and specific test in the detection of acute hepatitis C in HIV infected subjects

R. Carney, D. Maranao, R. Sudra, S. Chaytor, W. Labbett, M. Johnson, A. Rodger, S. Bhagani, D. Webster, T. Haque

Research output: Contribution to journalMeeting abstractpeer-review

Abstract

Background: Guidelines have been established in the UK and Europe for the monitoring of HIV patients at risk of hepatitis C (HCV) acquisition including annual HCV antibody (anti-HCV) testing in MSM. Blood samples testing positive for anti-HCV should be screened for HCV RNA by PCR. PCR testing is costly, labour-intensive and requires advanced technical skills and specialist equipment. Newer, automated and highly sensitive assays have been introduced that detect HCV core antigen (cAg) which might compliment anti-HCV testing and supplement RNA testing. These assays are less expensive and time-consuming and may be as effective in detecting HCV. Their use in the context of acute HCV infection in HIV has not been evaluated. Methods: A fully automated immunoassay for the detection and quantification of HCV cAg was employed (Abbott Diagnostics). Three groups of samples were tested: (1) Commercial HCV seroconversion panels (genotypes 1a, 1b, 2b & 3a) were tested (n=45), (2) HCV RNA negative samples (n=41), and (3) HIV patients presenting with acute HCV between 01/01/08 and 31/08/13 (n=30). The detection threshold was assessed using a dilution series of the WHO HCV RNA Standard. Results: HCV cAg was detected in all samples from each genotype seroconversion panel where HCV RNA was also detected. In 23 cases, anti- HCV antibody had not yet become detectable. 40 of the 41 HCV RNA negative samples tested were negative for HCV cAg (1 false positive). The corresponding HCV viral loads of the 30 samples from patients with acute HCV were 70 to 12,145,500 IU/mL (median 2,144,937). All 30 were positive by HCV cAg assay with 1/30 falling within the “grey zone” of reactivity (0.13 pg/mL). There were no false negative results. Taken together (75 positive and 43 negative samples), the test’s characteristics were: Sensitivity 100%, Specificity 97.7%, positive predictive value 97.6%, negative predictive value 100%. The WHO standard titration showed that HCV RNA levels of 1250 IU/mL were reliably detected by the cAg assay whereas viral loads of 625 IU/mL were not. There was a good correlation between HCV viral load and cAg quantification, r 2 = 0.99. Conclusion: Using the HCV core antigen assay in our setting (in place of HCV RNA testing) would not have missed any cases of acute HCV. The test is a rapid, sensitive and specific test for HCV infection with numerous advantages over current monitoring algorithms in HIV including a test price of one-third RNA testing
Original languageEnglish
Pages (from-to)8
Number of pages1
JournalHIV Medicine
Volume15
Publication statusPublished - 1 Apr 2014

Keywords

  • Science & Technology
  • Life Sciences & Biomedicine
  • Infectious Diseases

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