for Health Care Providers
Definitions of Response
HCV RNA decline during therapy is highly associated with the likelihood of achieving an SVR. Attaining rapid virologic response (RVR), extended RVR (eRVR), and early virologic response (EVR) can provide guidance as to the likelihood of achieving an SVR (refer to Figure 1) (11, 12, 13, 14, 15) . A sensitive real-time quantitative HCV RNA PCR assay should be used to assess viral response. The assay should have a lower limit of quantification for HCV RNA of ≤ 25 IU/ml, and a lower limit of detection of 10-15 IU/ml. The lower limit of detection of <10-15 IU/ml should be used for decision-making to determine treatment duration and RGT (34, 35) . Careful virological monitoring and prompt assessment of HCV RNA results are necessary to determine when treatment is futile and should be halted to avoid the emergence of resistance.