Of the patients positive for HCV RNA, those with negative HCV antibodies (n = 79; 3.5% of the initial 2243 patients) were considered as definite acute hepatitis C. Of the 322 with positive HCV antibodies, 114 had ALT levels lower than 10 times ULN, and were therefore no longer considered potential acute hepatitis C cases. This evidence concerns the gene GPT and hepatitis C virus infection.