Journal of Clinical Virology 44 (2009) 78–80 Contents lists available at ScienceDirect Journal of Clinical Virology journal homepage: www.elsevier.com/locate/jcv Short communication Diagnosing acute hepatitis C in HIV-infected patients: Nucleic acid testing compared with antibody and antigen–antibody detecting methods Eleni Nastouli a,∗ , Emma C. Thomson b , Peter Karayiannis b , Janice Main b , Myra McClure b , David Muir a a Department of Virology, Imperial College Healthcare NHS Trust, St. Mary’s Hospital, Praed Street, London W2 1NY, United Kingdom b Department of Medicine, Imperial College London, St. Mary’s Hospital, Praed Street, London W2 1NY, United Kingdom article info Article history: Received 15 September 2008 Accepted 17 September 2008 Keywords: HIV Hepatitis C Nucleic acid testing Antibody abstract Background: Early diagnosis of hepatitis C virus (HCV) infection in HIV-infected patients has significant implications for patient management. However, the currently recommended serological screening strat- egy for identifying such patients could be improved. Little is known about the performance of routine antibody-only tests, compared with newer serological antigen–antibody detection assays and nucleic acid testing in this patient group. Objectives: To compare the performance of antibody and antigen–antibody detecting methods with nucleic acid testing in the diagnosis of acute HCV in HIV-infected individuals. Study design: 123 samples from 25 HIV-infected patients with acute HCV infection were tested retrospec- tively. The time of infection was estimated. The performance of antibody, antigen–antibody and nucleic acid detecting methods in diagnosing acute HCV infection was assessed and the sensitivity of the assays compared. Results: Only 20% of samples that were positive for HCV RNA were simultaneously positive for HCV antibody. In contrast, 68% of the total number of samples were positive and 32% negative by the antigen–antibody assay. Patients became antibody-positive on average 7 months after HCV RNA was detected. Conclusion: In HIV-infected patients nucleic acid testing is the most sensitive means of diagnosing acute HCV C infection. A serological assay offering combined detection of antibody and antigen enhances sen- sitivity of detection, compared to antibody-only assays. © 2008 Elsevier B.V. All rights reserved. 1. Introduction The estimated HCV seroprevalence in the 15–59-year-old of age group in the UK is estimated to be 0.72%. The prevalence of chronic HCV infection is estimated as 0.53%, assuming that 74% of anti- body (anti-HCV) positive population become chronically infected. 1 However, prevalence rates of up to 16% have been reported in HIV-infected individuals and an increase in incidence among HIV- infected men having sex with men (MSM) in London has been observed since 2002. 2 Co-infection with HCV increases the mor- bidity and mortality of HIV-infected patients and early diagnosis has important implications for the treatment and prognosis of both infections. 3,4 Current guidelines on co-infection estimate the false nega- tive antibody rate to be low. 5–7 However, testing for evidence of HCV RNA is recommended where acute HCV infection is sus- ∗ Corresponding author. Tel.: +44 2078867790; fax: +44 2078866505. E-mail address: e.nastouli@imperial.ac.uk (E. Nastouli). pected or when liver function tests are abnormal. Antibody testing for HCV relies on enzyme immunoassays (EIAs) and chemilumi- nescence immunoassays (CIAs) that became available soon after the identification of the virus in 1989. Recently, the MONOLISA HCV antigen–antibody Ultra assay (Bio-Rad, Marnes la Coquette, France) has been evaluated and reported as a possible alternative for screening and diagnosis of HCV infection. 8 The objective of this study was to evaluate the antigen–antibody assay in the context of acute HCV in HIV-infected individuals and to compare its performance with other means of diagnosing HCV infection, namely antibody-only assays and nucleic acid tests. 2. Methods 2.1. Patients and clinical samples Twenty-five patients from our cohort of MSM patients with HIV infection were investigated for HCV infection. They were either investigated for abnormal liver function tests and followed post- exposure to document high-risk events, or found to have recently 1386-6532/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jcv.2008.09.008