HCV diagnosis: will core antigen testing replace viral RNA?

  • van Tilborg M & al.
  • Lancet Gastroenterol Hepatol
  • 28 Sep 2018

  • from Yael Waknine
  • HCV Clinical Digest
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Takeaway

  • HCV core antigen testing offers a potentially cost-saving alternative to HCV RNA assays for diagnosis, but may not adequately determine sustained virologic response at 12 weeks post-therapy (SVR12).

Why this matters

  • Cost savings for national screening programs could translate to improved access to direct-acting antivirals.

Study design

  • Study of 10,006 serum samples tested for HCV antibodies by commercial laboratories in Ontario, Canada.
  • Data for 202 patients treated for HCV in Canada, Germany, and the USA.
  • Funding: Abbott Diagnostics, Toronto Centre for Liver Disease.

Key results

  • Screening study:
    • 75 of 80 HCV RNA+ samples also tested positive for core antigen (sensitivity, 94%; 95% CI, 86%-98%); the remaining 5 showed low-level viremia.
    • No HCV RNA-negative samples were core antigen-positive (specificity, 100%; 95% CI, 94%-100%).
  • Clinical cohort:
    • 1% of baseline samples (2/202) tested negative for HCV core antigen (HCV RNA, 468 and >2,000,000 IU/mL, respectively).
    • Core antigen showed good concordance with HCV RNA at 12 weeks post-therapy (r=0.97; P<.0001 but patients with svr12 tested positive and relapse negative.>
  • Use of HCV core antigen vs HCV RNA testing to confirm diagnosis yielded cost-savings of $0.29-3.70 CAD per patient screened, depending on use of confirmatory HCV RNA.

Limitations

  • Retrospective design.