We have studied 933 volunteer blood donors from May to July, 1990. After a interview and screening tests for syphilis, Chagas disease, malaria and HIV, they underwent an enzyme immunoassay for HBsAg, anti HBc and anti HCV antibodies. Alanine aminotransferase (ALT) serum levels were determined by auto analyser. Most blood donors were male with mean age of 33 years (19-65). Anti HCV prevalence was 3.1% (29 from 933 blood donors). Among anti HCV+, blood donors, 44.8% (13/29) had ALT 40 UI/L, 31% (9/29) were anti HBc+ and 17.2% (5/29) had both surrogate markers simultaneously. From 109 donors with ALT 40 UI/L, 13 (11.9%) were anti HCV+, while among 153 anti HBc+ donors, the anti HCV was 5.8%.
Conclusions: 1) we found a higher anti HCV prevalence among our blood donors than previous published reports from other countries; 2) our data show that surrogate assays do not adequately identify anti HCV blood donors, 41.4% of them would not have been excluded by anti HBc and ALT tests alone; 3) there were a correlation between anti HCV positivity with a sample to cutoff optical density ratio equal or greater than 4 and elevated ALT serum levels.