Improving Diagnosis of Hepatitis C Virus Infection Using Hepatitis C Core Antigen Testing in a Resource-Poor Setting

Hepatitis C virus core antigen: A diagnostic and treatment monitoring marker of hepatitis C virus in Indian population

BACKGROUND

The diagnosis and treatment monitoring of hepatitis C is quite challenging. The screening test, i.e. antibody assay, is unable to detect acute cases, while the gold standard hepatitis C virus (HCV) reverse transcriptase polymerase chain reaction (RTPCR) assay is not feasible in resource-limited countries such as India due to high cost and infrastructure requirement. European Association for the Study of the Liver and World Health Organization have approved a new marker, i.e. HCV core antigen (HCVcAg) assay, as an alternative to molecular assay. In this study, we have evaluated HCVcAg assay for diagnosis and treatment monitoring follow-up in Indian population infected with hepatitis C.

METHODS

Blood specimen of 90 clinically suspected cases of acute hepatitis C were tested simultaneously for anti-HCV antibody assay via ELISA (enzyme-linked immunoassay), HCVcAg assay by chemiluminescence immune assay (CLIA) and HCV RTPCR VL (viral load) assay. Thirty-four HCV RTPCR positive patients were further enrolled in treatment monitoring group whose blood samples were tested at the beginning of treatment, two weeks, four weeks and 12 weeks via HCV core Ag assay and HCV RTPCR Viral Load assay.

RESULTS

Considering HCV RTPCR as gold standard, diagnostic performance of HCV core Ag assay and anti-HCV antibody assay was evaluated. The sensitivity and specificity of HCV core Ag assay were higher than that of anti-HCV Antibody assay, i.e. 88.3% and 100% vs. 23.3% and 83.3%, respectively. The overall diagnostic accuracy of HCV core Ag assay was 92.20%. Among treatment follow-up group, HCV core Ag levels correlated well with HCV viral load levels, at the beginning of treatment (baseline) till 12 weeks showing highly significant Spearman rank correlation coefficient of > 0.9 with HCV viral load levels.

CONCLUSIONS

HCV core Ag assay is a cost-effective, practically feasible substitute of HCV RTPCR viral load assay for diagnosis as well as long duration treatment monitoring of hepatitis C infection in resource-limited settings.

HCV Self-Testing to Expand Testing: A Pilot Among Men Who Have Sex With Men in China

Background

Hepatitis C virus self-testing (HCVST) may increase test uptake especially among marginalized key populations such as men who have sex with men (MSM). We conducted an observational study to assess the usability, acceptability and feasibility of HCVST among MSM in China.

Methods

An observational study with convenience sampling was performed among MSM in Guangzhou, China in 2019. The OraQuick® HCV Rapid Antibody Test kits were used in this study. Participants performed all 12 HCVST steps and interpreted the results in the presence of a trained observer. Usability was defined as the number and percentage of participants who completed all testing steps correctly without assistance and interpreted the results correctly. Inter-reader concordance was calculated as the percentage agreement between the results interpreted by the participant and those interpreted by a trained staff member. The same process was used to estimate inter-operator agreement between the self-testing and professional use test results. Acceptability was assessed using an interviewer-administered semi-structured questionnaire.

Results

Among 100 participants with median age 27 (interquartile range 23-30) years, 4% reported prior history of HCV testing, 41% reported using blood-based HIV self-testing in the past, 54% (95%CI: 43.7-64.0%) completed all self-testing steps correctly without assistance and interpreted the results correctly. Both the inter-reader and inter-operator concordance were excellent at 97% (95%CI: 91.5-99.4%) and 98% (95%CI: 93.0-99.8%), respectively. The majority rated the HCVST process as very easy (52%, 95%CI: 41.8-62.1%) or easy (41%, 95%CI: 31.3-51.3%), 76% (95%CI: 66.4-84.0%) were willing to use HCVST again, and 75% (95%CI: 65.3-83.1%) would recommend it to their family and friends.

Conclusions

Our findings demonstrate that oral fluid HCVST has high usability and acceptability among Chinese MSM. More implementation research is needed to plan how best to position and scale-up HCVST alongside other facility-and community-based testing approaches and ensure data linkage into health systems.