Using the prevalence of an elevated serum alanine aminotransferase level for identifying communities with a high prevalence of hepatitis C virus infection.

BACKGROUND: Antibody to hepatitis C virus (anti-HCV) is a widely accepted method for the diagnosis of HCV infection. However, it is too expensive to use in large-scale health surveys.
OBJECTIVE: To investigate the use of the serum alanine aminotransferase (ALT) level to predict the prevalence of HCV infection. PATIENTS AND METHODS: A sample of 6095 residents aged 35 years old or older in a small township of southern Taiwan, Republic of China, were examined in a community health survey. These persons were walk-ins to the government-sponsored stations after an intensive health promotion for this survey. Blood samples were obtained and analyzed for serum ALT levels. The presence of hepatitis B surface antigen and anti-HCV were determined by enzyme immunoassay methods.
RESULTS: The overall prevalences of hepatitis B surface antigens(+), anti-HCV(+), and elevated ALT levels were 11.8%, 15.0%, and 7.5%, respectively. Among the 13 villages in this community, the prevalence of hepatitis B surface antigen(+) ranged from 6.8% to 17.3%, anti-HCV(+) ranged from 7.2% to 37.6%, and an elevated ALT level ranged from 5.8% to 16.5%. A strong positive correlation was found between the prevalence of an elevated ALT level and anti-HCV(+) (r= 0.91, Spearman rank correlation; P<.001). However, nearly 0 correlation (r= -0.05, P=.87) was obtained between the prevalence of an elevated serum ALT level and hepatitis B surface antigen(+).
CONCLUSION: The prevalence of an elevated serum ALT level in a community is a strong indicator of its prevalence of anti-HCV(+), even in areas where there is a similar prevalence of hepatitis B virus infection. This result is useful for economically identifying hyperendemic communities with HCV infection.