of 1,533 study subjects ( mean age 21.9 +/- 13.2 years ; range , 4 months to 80 years ) , 11.4 % were positive for hbsag and 56.2 % were seropositive for at least one hepatitis b marker ( hbsag , anti-hbs , or anti-hbc ) .
C0019163
hepatitis b
C0019168
hbsag