HCV core antigen plays an important role in the fight against HCV as an alternative to HCV-RNA detection.

OBJECTIVE: To discuss the clinical significance of HCV-cAg testing in the diagnosis, activity determination, and monitoring of therapeutic effectiveness of HCV infection and its advantages compared with HCV-RNA and anti-HCV antibodies detection. METHODS: By summarizing the published literature, the advantages and significance of HCV core antigen detection were sought. RESULTS: The expression of HCV-cAg is highly consistent with that of HCV-RNA, but compared with HCV-RNA, detection of HCV-cAg is easy to operate, time saving, and low cost. HCV-cAg can be detected within 12~15 days after infection, and the window period can be shortened by5~7 weeks. HCV-cAg is a serological indicator of virus replication, which can distinguish previous infection of HCV or current infection. HCV-cAg detection is more suitable for immunocompromised, hemodialysis, organ transplant patients. HCV-cAg also can be used to monitor antiviral efficacy and predict sustained virological response (SVR). CONCLUSION: HCV core antigen has similar clinical sensitivity to NAT and can be used as a substitute for HCV-RNA in the diagnosis of virus infection. Combined detection of HCV-cAg and antibody serology can help doctors detect HCV infection earlier, accurately diagnose different stages of HCV infection, and evaluate the therapeutic effect of antiviral drugs, which are beneficial in the prevention and treatment of hepatitis C.