Meta‐analysis: diagnostic accuracy of hepatitis C core antigen detection during therapy with direct‐acting antivirals

Background: Treatment of hepatitis C virus (HCV) infection with direct-acting antivirals (DAAs) is monitored by assessing plasma HCV-RNA load. However, detection of HCV core antigen (HCVcAg) may be an alternative. Aim: To evaluate the diagnostic performance of the HCVcAg assay to monitor the efficacy of DAAs in HCV-infected patients Methods: We performed searches in multiple electronic databases until 6 July 2022, of studies evaluating the HCVcAg detection in plasma or serum compared with the HCV-RNA test (gold standard). We calculated pooled measurement at 2 and 4 weeks of treatment, and at end-of-treatment (EOT), as well as sustained virological response (SVR; 12 weeks after EOT). Results: We selected 16 studies from 2016 to 2022, with 3237 patients and 8958 samples. Overall, the diagnostic performance and clinical utility of the HCVcAg assay were poor at week 2 (sensitivity = 0.40, specificity = 0.96, positive likelihood ratio (PLR) = 9.16, negative likelihood ratio (NLR) = 0.63, and area under the summary receiver operating curve (SROC) = 0.57), fair at week 4 (sensitivity = 0.30, specificity = 0.90, PLR = 3.18, NLR = 0.77, and AUC = 0.79), acceptable at EOT (sensitivity = 0.40, specificity =0.98, PLR = 16.54, NLR = 0.62, and AUC = 0.97) and excellent for SVR (sensitivity = 0.94, specificity = 0.99, PLR = 107.54, NLR = 0.06, and AUC = 0.99). Conclusions: The HCVcAg assay may be helpful for monitoring the efficacy of HCV treatment with DAAs in HCV-infected patients at EOT and for documenting SVR, but not at weeks 2 and 4 of treatment due to poor diagnostic performance.