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Improving Diagnosis of Hepatitis C Virus Infection Using Hepatitis C Core Antigen Testing in a Resource-Poor Setting
Ayswarya Kannan1, Lalitha Biswas2, Anil Kumar1
1Amrita Vishwa Vidyapeetham, Amrita Institute of Medical Sciences, Department of Microbiology, Ponekara, Kochi, Kerala, India.
Insights
The hepatitis C virus (HCV) core antigen test is a highly specific alternative to HCV RNA testing for confirming HCV infections, especially in low-resource settings. While less sensitive, it aids in understanding the true prevalence of HCV in populations.
Area of Science:
- Virology
- Immunology
- Diagnostic Medicine
Background:
- Hepatitis C virus (HCV) infection diagnosis relies on antibody (anti-HCV) and RNA detection.
- Confirming anti-HCV results is crucial for accurate diagnosis and patient management.
Purpose of the Study:
- To evaluate the hepatitis C virus (HCV) core antigen test as a potential alternative confirmatory assay to HCV RNA testing.
- To assess the diagnostic performance of the HCV core antigen assay in confirming anti-HCV results.
Main Methods:
- Analyzed sera from 156 patients for anti-HCV, HCV core antigen, and HCV RNA.
- Utilized chemiluminescent microparticle immunoassay for anti-HCV and HCV core antigen detection.
- Employed RT-PCR (artus HCV RG RT-PCR Kit) for HCV RNA quantification.
Main Results:
- HCV core antigen assay demonstrated high specificity (100%) and positive predictive value (100%).
- Diagnostic sensitivity was 77.35%, with good correlation between HCV core antigen levels and HCV RNA quantification (r=0.872).
- 13 samples with low viral load (<4000 IU/mL) were negative for HCV core antigen; all gray-zone samples were RNA positive.
Conclusions:
- The Architect HCV core antigen assay is a highly specific and valuable tool for HCV diagnosis.
- Its utility is significant in low-income settings where HCV RNA testing is inaccessible or unaffordable.
- HCV core antigen testing can provide insights into the actual burden of HCV infection, identifying cases missed by RNA testing alone.
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.
