Multicenter evaluation of hepatitis C RNA levels among female injection drug users.

The purpose of this investigation was to identify factors that determine the blood level of hepatitis C virus (HCV) RNA. By use of a quantitative polymerase chain reaction assay, the level of HCV RNA was ascertained in stored serum samples from 676 women enrolled in a multicenter prospective investigation who were seropositive for anti-HCV antibodies. HCV RNA levels ranged from undetectable to 22.4x106 copies/mL in these women. Among the 520 women with detectable HCV RNA, levels were higher among those who were >41 years old and those who had human immunodeficiency virus (HIV) infection. After adjusting for age in a multivariate linear regression model, HCV RNA levels were more strongly associated with HIV RNA levels than with CD4(+) lymphocyte counts. However, <6% of person-to-person variance was explained by the factors evaluated. Additional research is needed to ascertain what determines the level of HCV RNA in blood.