Clinical Laboratory Testing in the Era of Directly Acting Antiviral Therapies for Hepatitis C

Abstract

Directly acting antiviral (DAA) combination therapies for chronic hepatitis C virus (HCV) infection are highly effective, but treatment decisions remain complex. Laboratory testing is important to evaluate a range of viral, host, and pharmacological factors when considering HCV treatment, and patients must be monitored during and after therapy for safety and to assess the viral response. In this review, we discuss the laboratory tests relevant for the treatment of HCV infection in the era of DAA therapy, grouped according to viral and host factors.

Keywords: directly acting antiviral therapy; hepatitis C virus; viral resistance.

FIG 1

Timing of laboratory testing for treatment of hepatitis C. The schematic shows the timing of host, virus, and safety laboratory testing prior to, during, and following combination DAA therapy for the treatment of chronic hepatitis C. Regimen-specific testing is color-coded according to regimen. Abbreviations: EOT, end of therapy; HIV, human immunodeficiency virus; RAV, resistance-associated variant; CBC, complete blood count; GFR, glomerular filtration rate; LFT, liver function testing; Hgb, hemoglobin. *, indicated if patient is cirrhotic; +, repeat as clinically indicated.

FIG 2

NS5A inhibitors and NS5A resistance-associated variants (77–80, 87). Numbers denote fold changes in reduced susceptibility to the NS5A inhibitor for the indicated amino acid substitution, rounded to the nearest integer.