How long should a person wait to donate blood or have an HBsAg blood test after a dose of hepatitis B vaccine?

It is advisable to wait at least 4 weeks. Published studies have found that transient HBsAg-positivity can be detected for up to 18 days after HepB vaccination (up to 52 days among hemodialysis patients). This does not mean the person is infected with HBV. However, donating too close to receipt of HepB could cause a person to be permanently deferred from blood donation if that person tests transiently HBsAg positive after the vaccine dose.