13. Documented negative test for HIV, HBV and HCV. For HBV serology, the determination of HBsAg, anti-HBsAg Ab and anti-HBcAg Ab is required. In patients with serology documenting previous exposure to HBV (e.g. anti-HBs Ab with no history of vaccination and/or anti-HBc Ab) negative serum HBV-DNA is also required.