I think it is great that you are willing to take on the responsibility of treating this patient’s chronic hepatitis C. In these cases where positive anti-HBc, negative HBsAg, and negative HBsAb, this can be from past resolved HBV infection with loss of titer of the HBsAb or from a false positive. Here I typically check the HBV DNA and HBV e Antigen if Immunocompromised or prior to starting HCV therapy. This is also a group of patients that we would vaccinate (as long as HBV DNA titer is negative). I’m sure you know, but After initiating HCV treatment, we typically send an HCV viral load as well as CBC, creatinine, and LFTs at week 4 of treatment to ensure that the therapy is working (the DNA should be undetectable at this point) and there are no adverse effects. We then check an HCV viral load at 12 weeks after therapy is concluded to confirm sustained virologic response (SVR). I hope this helps. Please let me know how the treatment goes.
AASLD Practice guidelines on the treatment of hepatitis C, AASLD website, 2019 Update on prevention, diagnosis, And treatment of chronic hepatitis B: AASLD Hepatitis B guidance 2018. Hepatology: volume 67, No 4, 2018