Methods for determining chronic hepatitis C infection are provided by the
present invention. The methods generally involve determining the optical
density of fluid samples which have tested positive for hepatitis C
infection using an antibody-based assay. The optical density can then be
used to determine in a predictive or probability-based manner whether the
fluid sample contains chronic hepatitis C infection or whether the fluid
sample merely contains antibodies to hepatitis C infection without
resorting to costly molecular detection methods. Thus, the present
invention permits differentiation between individuals who have cleared
hepatitis C infection but still test positive in an antibody-based assay
from individuals having chronic hepatitis C infection.