Hepatitis C virus screening and intravenous immunoglobulin safety in Japan.

To obtain safe blood products, contaminants in source plasma must be eliminated through screening. Second-generation agglutination tests performed as part of donor screening have been shown to reduce the risk of hepatitis C virus (HCV) infection to 0.024% (1/4124) per unit of donated blood. These tests, as well as the third-generation enzyme-linked immunosorbent assay, significantly shortened the window of infectivity (the period between infection and antibody production) through more sensitive and specific recognition of anti-HCV antibodies in early-stage HCV infection. Earlier detection may reduce the risk of contamination of plasma with the high viral load that can be present in early-stage HCV infection without detectable anti-HCV antibodies. Because alanine aminotransferase levels increase before detectable seroconversion occurs in the window of infectivity, screening for alanine aminotransferase levels was found to be useful in determining which sources of plasma should be eliminated because of HCV contamination.