Despite widely available lab tests and curative treatment, hepatitis C virus (HCV) remains one of the most common blood-borne infections in the United States.

Researchers from Quest Diagnostics, worked with the Centers for Disease Control and Prevention (CDC), Harvard Medical School and HealthVerity to publish findings of a study that reveals the scale of gaps in care – and why HCV continues to infect so many people.

Published in the Journal of the American Medical Association’s JAMA Network Open, the study, “Comparison of Care Cascade Outcome Measures for Hepatitis C Among Insured US Adults,” found that among more than 4.5 million individuals tested, many with lab-confirmed evidence of HCV never received therapy and, of those that did, many never had follow-up testing to make sure the therapy worked.

The study evaluated adults who underwent HCV antibody, RNA, or genotype testing between January 2019 and June 2022 across the US. Individuals who ever had HCV infection were included in the study if they had positive or detectable RNA, continuous insurance enrollment, and no evidence of treatment in the 60 days prior to their positive test date.

Key findings:

• Only 40% of those with evidence of initial HCV infection had subsequent laboratory-based evidence of viral clearance. 
• Among those with initial HCV infection who did not have a subsequent RNA test to assess viral clearance, most (78%) had no evidence of initiating treatment.
• Only 26% of those with initial HCV infection had a negative or undetectable HCV RNA result after documented treatment initiation. 

The findings highlight the tremendous gap in follow-up care, treatment, and clearance of people with HCV infection. Reflecting on the study, co-author Dr. William Meyer, former technical director and current consultant for Quest Diagnostics said: “This uniquely large analysis of both laboratory and prescribing data reveals troubling gaps in both testing and treatment for hepatitis C in the United States, despite widespread availability of both testing and curative treatment.”

Strengths of the study include the multiple data strategies used to measure HCV viral clearance and sustained virologic response, as well as the large participant population. Limitations include the possibility that treatment was not captured in insurance claims used in the analysis.

According to the CDC, HCV infection was estimated to affect more than 2.4 million Americans from 2017–2020 and, if inadequately treated, may lead to advanced liver disease or even death. However, highly effective direct acting antiviral (DAA) therapy is widely available, trending towards the possibility of curative treatment. 

Quest and CDC have previously collaborated on several studies aimed at improving hepatitis public health research based on insights from Quest’s laboratory data.