Hepatitis C virus window-phase infections: closing the window on hepatitis C virus.

Background: The detection of hepatitis C virus (HCV) infection is of major importance for the prevention of transfusion-transmitted hepatitis. The testing of donations by nucleic acid testing (NAT) techniques may not be feasible or economic. Combined antigen and antibody assays are now available, and the performance of two combined assays on window-phase donations is evaluated.