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.
Ayswarya Kannan, Dr. Lalitha Biswas, Anil Kumar, Jessy Kurian, Anjaly S. Nair, Parasmal Suresh, Shine Sadasivan, and Dr. Raja Biswas, “Improving Diagnosis of Hepatitis C Virus Infection Using Hepatitis C Core Antigen Testing in a Resource-Poor Setting.”, Rev Soc Bras Med Trop, vol. 54, p. e02532020, 2021.