Abstract
Serum samples from 1,765 consecutive Sardinian blood donors, negative for hepatitis B surface antigen (HBsAg) and for antibodies to human immunodeficiency virus (HIV) (anti‐HIV), were evaluated for the presence of antibodies to hepatitis C virus (anti‐HCV) by second‐generation ELISA. Anti‐HCV was detected in 25 (1.45%) of the 1,765 donors examined. Anti‐HCV was found in 15 of the 1,690 (0.9%) donors with normal alanine aminotransferase (ALT) and in 10 of the 75 (13%) donors with elevated ALT (P < 0.0001). Of the 15 anti‐HCV‐positive donors with normal ALT, only five (33%) were confirmed to be positive by second‐generation RIBA, six (40%) were indeterminate, while four (27%) were RIBA negative. HCV RNA, as detected by polymerase chain reaction (PCR) using a set of primers from the 5′‐noncoding region, was found in six of the 15 (40%) donors with normal ALT, including five RIBA, positive and one indeterminant. Of the 10 anti‐HCV‐positive donors with elevated ALT, all were RIBA positive and eight (80%) had detectable HCV RNA. Thus, among ELISA‐reactive donors, those with elevated ALT had a significantly higher probability of being positive for secondgeneration RIBA and HCV RNA compared to those with normal ALT levels (P = 0.028). None of the 65 donors with elevated ALT but negative for anti‐HCV by ELISA had detectable serum HCV RNA, as compared to eight of 10 anti‐HCV ELISApositive donors (P < 0.0001). However, although negative for HBsAg, 12 of the 65 (18%) had serum HBV DNA by PCR. This study demonstrates that the combined use of second‐generation ELISA and RIBA anti‐HCV assays is highly effective in identifying HCV infection, whereas the specificity of ELISA alone for the screening of blood donors with normal ALT values appears to be limited. In contrast, in donors with elevated ALT levels, there is a positive correlation between second‐generation assays (ELISA and RIBA) and HCV viremia. The high proportion of inapparent HBV infection in blood donors with elevated ALT levels underlines the importance of this test for the prevention of transfusion‐associated viral hepatitis.