Reuters Health Information: HCV core antigen cost-saving alternative for diagnosing hepatitis C

HCV core antigen cost-saving alternative for diagnosing hepatitis C

Last Updated: 2018-10-26

By Will Boggs MD

NEW YORK (Reuters Health) - HCV-core-antigen testing is a cost-saving alternative to HCV RNA testing for diagnosing hepatitis C infection, according to a retrospective study.

"Our study nicely validates the recommendation of World Health Organization (WHO) and European Association for the Study of the Liver (EASL) that HCV core antigen can be used in place of HCV RNA, particularly in regions where cost is a major consideration," said Dr. Jordan J. Feld of the University of Toronto, in Canada.

"HCV core antigen can be reliably used to confirm the presence or absence of infection and can be used for treatment monitoring when it is required," he told Reuters Health by email.

HCV core antigen is more stable at room temperature than is HCV RNA, allowing for unrefrigerated transport. It can be tested on the same platform that is used for HCV antibodies. HCV-RNA testing by reverse-transcription quantitative PCR is also more expensive.

Dr. Feld and colleagues sought to determine if HCV core antigen could be used for confirmation of HCV infection in HCV antibody-positive samples, as well as for on-treatment monitoring and assessment of treatment response in samples from patients treated with direct-acting antivirals.

In more than 10,000 screening samples, HCV core antigen was 94% sensitive and 100% specific for confirming viremia, the team reports in The Lancet Gastroenterology & Hepatology, online September 28.

The diagnostic performance of HCV core antigen among patients receiving antiviral treatment varied at different treatment time points. Sensitivity ranged from 34.6% at four weeks of treatment to 50.0% at the end of treatment, 98.2% at follow-up week 12 and 100% at follow-up week 24.

Specificity ranged from 86.6% at four weeks to 97.5% at the end of treatment, 97.7% at follow-up week 12 and 100% at follow-up week 24.

Based on these estimates, a screening program in which HCV core antigen replaced HCV-RNA testing for confirmation of viremia in patients who test positive for HCV antibodies would save 0.29 Canadian dollars (US$ 0.22) per person screened.

If negative HCV-core-antigen results excluded the need for HCV-RNA testing for confirmation, the savings would amount to 3.70 Canadian dollars (US$ 2.81) per patient screened.

The use of confirmatory HCV-RNA testing for samples that test negative for HCV core antigen would cost an estimated 25,401 Canadian dollars (US$ 19,325) per quality-adjusted life-year (QALY), still well within most willingness-to-pay thresholds.

"People who test HCV-antibody positive but HCV-core-antigen negative should consider having an HCV RNA to confirm the absence of infection," Dr. Feld said. "For the individual, this approach is definitely the most certain because a small percentage of people who have the infection will test core-antigen negative. However, for countries/regions planning widespread screening, it may be reasonable to use core antigen only to confirm infection, with significant potential cost savings by avoiding HCV RNA testing."

He added, "Although we were overall very impressed with the performance of HCV core antigen, the few discordant results at the time of SVR12 were notable. This critical time point determines whether an individual is cured. In almost cases, HCV core antigen agreed with HCV-RNA results at SVR12; however, the risk that someone is incorrectly deemed to be cured or scheduled for unnecessary retreatment is obviously a concern. As a result, it would still be prudent to use HCV RNA 3 months post-treatment to determine whether an individual is cured."

These findings "provide optimism for a major simplification and scale-up of hepatitis C screening and treatment worldwide," write Dr. Maud Lemoine from St. Mary's Hospital, Imperial College London, and Dr. Karine Lacombe from St. Antoine Hospital in Paris in a linked editorial.

Dr. Rosanna W. Peeling from London School of Hygiene and Tropical Medicine, who recently reviewed innovations in viral-hepatitis testing technologies and approaches, told Reuters Health by email, "The most interesting and useful finding in this paper is the confirmation that HCV-core-antigen testing can be used as an alternative to HCV-RNA testing as a marker of viremia. This means that in resource-limited settings where molecular tests to detect virus are neither affordable nor accessible (because of lack of laboratories that can perform such assays), more HCV-antibody-positive patients can now be tested to determine if they require treatment."

"Development of a rapid test to detect HCV core antigen would be useful for immediate confirmation of viremia in patients found to be positive for HCV antibodies," said Dr. Peeling, who was not involved in the new study. "This 2-test combination can reduce loss to follow up in the cascade of care for HCV."

Abbott Diagnostics partially funded the study, employed one of the 20 authors, and had various relationships with five others.

SOURCE: https://bit.ly/2JgxxSI and https://bit.ly/2AupCyJ

Lancet Gastroenterol Hepatol 2018.

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