New direct-acting antivirals for patients with chronic HCV infection: can we monitor treatment using an HCV core antigen assay?

•HCV-Ag assay presents a strong correlation compared with RT-PCR.•HCV-Ag assay correctly classified all patients with sustained virological response.•HCV-Ag assay correctly detected all patients with treatment failures.•Viral load curves were almost the same both determined by RT-PCR and HCV-Ag.•HCV-Ag assay showed to be a reliable technique to monitor DAA treatments.

We evaluated the diagnostic usefulness of an HCV core antigen (HCV-Ag) assay in HCV-infected patients undergoing treatment with direct-acting antivirals. We analyzed 103 samples from 28 patients. Compared with RT-PCR, sensitivity was 96.2% and specificity was 100%. The correlation between techniques was excellent (Pearson coefficient: 0.871). HCV-Ag proved to be useful in patients with sustained viral response and in patients who experienced treatment failures.