Usefulness of Track-C (Total HCV Core Antigen) Assays in Anti-HCV Positive Patients

Yang, Sung Jin; Shin, Myung Geun; Kim, Soo Hyun; Cho, Deok; Kee, Seung Jung; Shin, Jong Hee; Suh, Soon Pal; Ryang, Dong Wook

Abstract

BACKGROUND
Virologic diagnosis of hepatitis C virus (HCV) infection is based on the use of sero-logic assays detecting specific anti-HCV antibodies, and then definitive diagnosis is made by detecting HCV RNA. Recently, newly developed Track-C (total HCV core antigen) test using an enzyme immunoassay (EIA) can detect and quantify total HCV core antigen in the peripheral blood of HCV-infected patients. In this study, the usefulness of Track-C test for the detection of HCV viremia was investigated by comparing the results with those of the HCV RNA test. METHODS: The study group consisted of 159 sera including 72 anti-HCV positive sera. The Track-C test was performed by enzyme immunoassay (Ortho Clinical Diagnostics, USA) with pretreatment for the dissociation of antigen-antibody complex. HCV RNA test was performed by HCV in house RT-nested PCR method. Results were calculated for the sensitivity, specificity and efficiency by comparing to each other. RESULTS: The efficiency between HCV RNA and Track-C was 77.4% for the 72 anti-HCV positivesera. Comparing with the results of HCV RNA, Track-C assay showed the sensitivity and specificity of 56.0% and 96.4%, respectively. Track-C assay demonstrated a relatively good linearity (R2=0.9836) and reproducibility (CV=4.4%) at high concentrations. CONCLUSIONS: Although the sensitivity of Track-C assay was not as high as that of HCV RT-PCR, a positive Track-C assay suggests the presence of HCV viremia, especially at higher concentrations. Track-C assay, therefore, may be used as a simple and supplementary test for HCV viremia and for follow-up monitoring.