Serum anti-M2 mitochondrial antibody (AMA-M2) was screened with immune colloidal gold technique in 6 008 individuals aged over 60 years who underwent health check-up in Xuhui District of Shanghai,the positive samples were retested with ELISA method.The results showed that 1.31％ (79/6 008) individuals were AMA-M2 positive; the positive rate was 0.82％ (18/2 186) in males and 1.60％ (61/3 822) in females.Eleven subjects with positive AMA-M2 underwent further investigation,8 cases were diagnosed as primary biliary cirrhosis (PBC) and the remaining 3 were highly suspected as PBC.All 11 individuals were abnormal in biochemical tests of liver function and/or clinical symptoms.