Detection of HCV RNA in subjects with antibody to hepatitis C virus among the general population of Fukuoka, Japan.

Volunteer blood donors and aged people who came to hospitals for a thorough physical checkup were surveyed to evaluate the exact prevalence of hepatitis C virus (HCV) infection in the general population of Fukuoka, Japan. We tested for antibody to HCV (anti-HCV) by second-generation assay and, to distinguish active HCV infection from past resolved infection, we tested for HCV RNA in reactive serum samples by polymerase chain reaction. The prevalence of anti-HCV was 286 (2.0%) of 14,341 subjects, increasing with advancing age, from 0.4% in the under-29 age group to 12.0% in the over-70 age group. There were no differences between sexes. HCV RNA was detected in 170 of 286 (59.4%) anti-HCV-positive subjects. The ratio of HCV RNA-positive to anti-HCV-positive subjects was higher in males than in females (P < 0.05) and decreased with advancing age, from 72.2% to 46.5%. The prevalence of elevated alanine aminotransferase (ALT) was only 15.9% in subjects with HCV RNA, higher in males (21.4%) than in females (8.3%) (P < 0.05). This study revealed that the prevalence of anti-HCV was high in the aged population, but that the ratio of HCV RNA-positive to anti-HCV-positive subjects was low, and most of the HCV RNA-positive subjects had normal ALT levels.