After the birth of a child from a hepatitis B mother is confirmed to be free of the hepatitis B virus, the main purpose of subsequent follow-up in the outpatient clinic is to observe changes in hepatitis B surface antibodies. It is usually necessary for the child to go to the hospital for a blood test to obtain specific values for the hepatitis B antibody series. As individual children have low antibodies, they may require a booster dose of the hepatitis B vaccine and a blood sample to improve their liver function, which can only be assessed after they have received the hepatitis B vaccine. Liver function can be done at the same time as the Hepatitis B Antibody Series, or can be done at separate times. It is generally recommended that this be done at the same time to avoid repeated blood draws for the child and to avoid the time-consuming cycle of separate visits. For liver function, the laboratory requires a fasting blood sample. For infants younger than 1 year old, you can fast for about 4 hours and complete the blood sample before the next feeding. If you visit my clinic on Fridays in the Pediatrics Department at Ditan Hospital, we usually see your child in the order of registration. Please make arrangements and bring any milk you need for your child’s care.