Improving the Diagnosis of Acute Hepatitis C Virus Infection with Expanded Viral Load Criteria

Abstract

Background.The diagnosis of acute hepatitis C virus (HCV) infection is imprecise because antibody testing does not differentiate between acute and chronic infection. Although virologic features, such as viral load fluctuations and low levels of viremia, have been noted to be characteristic of acute HCV infection, these parameters have not been used for diagnosis. Methods.We validated the use of these novel parameters (ie, viral load fluctuations >1 log and HCV RNA levels Results.Low-level viremia and viral load fluctuations were highly prevalent in our cohort of acute seroconverters (81% and 86%, respectively), whereas low-level viremia occurred in only 13% of control patients with chronic infection. With use of standard criteria, 37 inmates received a diagnosis of acute HCV infection. Among the 35 patients with HCV RNA detectable at baseline, we found low-level viremia to be highly prevalent (n=27; 77%); among patients with a minimum of 2 HCV RNA samples, we demonstrated viral fluctuations in more than one-third (n=9; 36%). Conclusions.The diagnosis of acute infection in HCV-seropositive patients is strengthened by the use of virologic parameters that are uncommon in chronic disease. Viral load fluctuations and low levels of HCV RNA should be incorporated into standard diagnostic criteria.