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Updated: Jul 25, 2025
A Protocol for Analyzing Hepatitis C Virus Replication
Published on: June 26, 2014
HCV Core-antigen Assay as an Effective Alternative to HCV RNA Quantification in Patients With Hepatitis C
Raquel Vieira1, Carlos Caldas2, Jose Antonio Carvalho2
1University of Trás-os-Montes and Alto Douro, Quinta dos Prados, Vila Real, Portugal.
Insights
The Hepatitis C virus (HCV) core antigen test offers a rapid, affordable alternative for diagnosing HCV infections. It shows high accuracy, especially with higher viral loads, aiding global HCV elimination efforts.
Area of Science:
- Hepatology
- Virology
- Infectious Diseases
Background:
- Hepatitis C virus (HCV) core antigen (Ag) testing is emerging as a rapid and cost-effective diagnostic alternative to molecular methods.
- Accurate and accessible diagnosis is crucial for achieving global HCV elimination goals.
Purpose of the Study:
- To evaluate the performance of the ARCHITECT® HCV Ag test compared to HCV RNA quantification (CAP/CTM).
- To assess the test's sensitivity, specificity, predictive values, and correlation with viral load and treatment stages.
Main Methods:
- Evaluation of the ARCHITECT® HCV Ag test against HCV RNA quantification (CAP/CTM) in 145 samples.
- Analysis of performance based on viral load (low vs. high) and treatment phases (treatment, end of treatment, sustained virological response).
Main Results:
- The HCV-Ag test demonstrated high sensitivity (88.9%), specificity (99.1%), PPV (97.0%), and NPV (96.4%) with a high correlation (r=0.890).
- Sensitivity decreased with low viral loads (<1,000 IU/ml) but increased with high viral loads (≥1,000 IU/ml).
- Good agreement was observed during treatment (k=0.789) and at the end of treatment (k=0.638), with excellent agreement in the sustained virological response group (k=1.000).
Conclusions:
- HCV-Ag testing is a viable alternative for routine HCV diagnosis, particularly when combined with antibody tests.
- It can help identify new infections efficiently, reserving molecular tests for discordant results.
Background/Aim:
Hepatitis C virus (HCV) core antigen (Ag) test has been increasingly applied as an effective alternative to conventional molecular tests allowing rapid and affordable diagnosis, which is of paramount relevance to achieve global elimination of HCV infection.
Materials And Methods:
ARCHITECT® HCV Ag test was evaluated in comparison with HCV RNA quantification test (CAP/CTM) to calculate its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and to determine their correlation level. Its performance, according to low and high viral load values and in different treatment stages [during treatment (T), at the end of the therapeutic protocol (EOT) and when sustained virological response (SVR) was evaluated].
Results:
In total, 145 samples were included. Considering CAP/CTM, the sensitivity, specificity, PPV and NPV of the HCV-Ag test were 88.9%, 99.1%, 97.0% and 96.4%, respectively, and the correlation among tests was high (r=0.890), with only five discordant results. A decrease in sensitivity was found for low viral load values (<1,000 IU/ml), but the opposite was verified for high viral concentrations (≥1,000 IU/ml). A good agreement was verified for the T and EOT groups (k=0.789 and k=0.638) and an excellent agreement in the SVR group (k=1.000).
Conclusion:
HCV-Ag seems to be an effective alternative that can be routinely combined with other faster and more accessible tests (e.g., HCV antibody tests) for the identification of new HCV infections in suspected patients, eventually reserving the molecular techniques for samples with discordant results.
