The efficiency of elevated serum alanine aminotransferase values for selecting subjects to be tested for hepatitis B or C infections in a large French population undergoing a medical checkup was investigated. For 5 consecutive weeks, serum alanine aminotransferase values were controlled in 9044 subjects; 308 subjects (202 males) were selected with alanine aminotransferase levels 1.2-fold above the normal value (58 iu/l for men, 34 iu/l for women). For each selected case, an age- and sex-cross-matched control was included. Of the 308 subjects with elevated alanine aminotransferase values, one was HBsAg positive and 15 (seven males) were anti-HCV positive. All anti-HCV sera tested by enzyme immunoassay were also positive by three immunoblots and 11/15 (73%) were HCV-RNA positive by reverse transcription-polymerase chain reaction. Of the 308 control subjects, two were HBsAg positive and four (two males) were weakly anti-HCV positive by enzyme immunoassay. Only one weakly anti-HCV positive serum was reactive by one immunoblot and all were HCV-RNA negative. This study shows the usefulness of alanine aminotransferase screening to detect hepatitis C virus infection in the general French population. Many of the anti-HCV positive subjects detected in this study were not aware of their hepatitis C virus seropositivity (12/15) or that they were viremic (11/15). Use of this low-cost assay will considerably reduce the number of subjects to be tested for hepatitis C virus serological status and therefore the cost. It may make possible the investigation of large populations by setting up public health programs to detect and treat hepatitis C virus. Hepatitis C virus infected subjects detected in these programs could benefit from medical follow up, including antiviral therapy.
