Hepatitis C core antigen: Diagnosis and monitoring of patients infected with hepatitis C virus

Abstract

Introduction: New efficient strategies are needed for the assessment of active hepatitis C virus (HCV) infection. The aim of this study was to evaluate the ability of HCV core antigen (HCV-cAg) as a marker of active HCV infection in newly diagnosed patients, for treatment monitoring, and for the detection of therapeutic failure.

Materials and methods: A prospective study was conducted at a regional reference hospital in Spain. HCV- cAg and viral load (RNA-HCV) were tested in plasma or serum samples from three patient groups: new

diagnosis, treatment monitoring, and treatment failure. The treatment monitoring group was tested at

the beginning of treatment, at 4 weeks post-initiation, at the end of treatment, and at 12 weeks post- treatment completion. The Architect HCV core antigen assay was performed for HCV-cAg testing, and

viral load was quantified with the Cobas 6800 system. Results: A total of 303 samples from 124 patients were analyzed. Excellent correlation was seen between HCV-cAg and HCV-RNA (R2 = 0.932). The optimal cut-off value was 3 fmol/l in the receiver operating characteristics curve analysis, and the area under the curve was 0.987 (95% confidence interval 0.972– 1.000). HCV-cAg sensitivity and specificity were 97% and 95%, respectively. Most diverging results were observed in the treatment follow-up group. Conclusions: HCV-cAg demonstrated good sensitivity and specificity as a marker for active HCV infection, new diagnosis, detection of antiviral therapeutic failure, and treatment monitoring.