Recent regulatory approvals of the NS3/4A protease inhibitors boceprevir and telaprevir launched a new therapeutic era for hepatitis C virus (HCV) genotype 1 infection. Decisions to shorten, extend, or stop treatment with these direct-acting antiviral (DAA) regimens require accurate quantification of serum HCV RNA levels. To effectively use DAA therapies, clinicians must understand performance characteristics of HCV RNA real-time PCR assays and the clinical significance of HCV RNA that is detectable below the lower limit of quantification. This review summarizes terms used to report HCV RNA viral load results, explains the analytical performance of the PCR assay used in the clinical trials of boceprevir and telaprevir, and compares currently available commercial assays.