It is recommended that levels of hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) in infants born to mothers with chronic hepatitis B are measured 3–12 months after they complete the primary vaccine course. Do not test the infant before 9 months of age, to avoid detecting anti-HBs from the hepatitis B immunoglobulin given at birth. See Infants born to mothers who are hepatitis B surface antigen–positive are recommended to receive both hepatitis B vaccine and HBIG.

Page history

Last updated: 
4 June 2018
Last reviewed: 
4 June 2018


hepatitis B surface antigen
antibody to hepatitis B surface antigen