20 Jun Single-Step Testing Can Improve Access To Hepatitis C Testing
MedicalResearch.com Interview with:
J. Morgan Freiman, MD
Infectious disease research fellow
Boston Medical Center
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Freiman: There are 130-150 million persons infected with chronic HCV with 75% of all cases occurring in low- and middle- income countries (LMICs). Diagnosis is a 2-step process that starts with screening for exposure with an assay that detects antibodies to HCV (anti-HCV), followed by nucleic acid testing (NAT) for persons with reactive anti-HCV to measure HCV ribonucleic acid (RNA) and confirm active viremia.
In LMICs diagnostic capacity is low, and fewer than 1% of patients are aware of their infection. Additionally, a significant proportion of patients who test positive for anti-HCV are lost to follow-up before nucleic acid testing. The 2-step diagnostic process is thus a major bottleneck to the HCV cascade of care. Testing for hepatitis C virus core antigen (HCVcAg) is a potential replacement for NAT.
Our systematic review evaluated the accuracy of diagnosis of active HCV infection among adults and children for 5 commercially available HCVcAg tests compared with NAT. We found that HCVcAg assays with signal amplification have high sensitivity, high specificity, and have the potential to replace NAT in settings with high HCV prevalence.
MedicalResearch.com: What should readers take away from your report?
Dr. Freiman: Several HCVcAg tests remain sensitivity and specific for the diagnosis of chronic HCV infection, though signal amplification appears necessary to reach a detection limit of approximately 3,000 IU/mL. While none of the available platforms is equal to NAT, the lower cost of testing may improve diagnostic capacity in the appropriate setting.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Freiman: Our study was limited by lack of data on covariates that may influence the level of circulating HCV virus (genotype, HIV and HBV co-infection) and thus affect the test performance. The epidemiology of chronic HCV viremia and impact of such covariates is not well described and would be very useful to inform the clinical level of detection necessary for an accurate screening and diagnostic HCV test.
MedicalResearch.com: Is there anything else you would like to add?
Dr. Freiman: Nucleic acid tests can detect as little as 15 IU/mL of circulating HCV RNA, but this technology is not widely available in most settings where the prevalence of HCV infection is highest. Access to testing is equally as important as accuracy in resource limited settings, and HCVcAg appears to be a potential target for at or near-patient test development.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Freiman JM, Tran TM, Schumacher SG, White LF, Ongarello S, Cohn J, et al. Hepatitis C Core Antigen Testing for Diagnosis of Hepatitis C Virus Infection: A Systematic Review and Meta-analysis. Ann Intern Med. [Epub ahead of print 21 June 2016] doi:10.7326/M16-0065
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