What blood test should be used to screen a pregnant person to prevent perinatal HBV infection?

Screening should be done with the hepatitis B surface antigen (HBsAg) test only. This blood test will tell whether a mother has current HBV infection that can be transmitted to the infant. Ordering a total antibody to hepatitis B core antigen (total anti-HBc) and/or anti-HBs are not useful when screening to prevent perinatal HBV infections and should not be included in screening during pregnancy for risk of perinatal HBV infection. Total anti-HBc will be positive in all HBsAg-positive people and anti-HBs is rarely positive in an HBsAg-positive person. Pregnant people who are found to be positive should be tested for HBV DNA to guide the use of maternal antiviral therapy during pregnancy for the prevention of perinatal HPV transmission (see MMWR 2018;67 [RR-1]:13).

An infant born to a mother for whom HBsAg screening test results during pregnancy are not available but other evidence suggesting maternal HBV infection exists (e.g., presence of HBV DNA, HBeAg-positive, or mother known to be chronically infected with HBV) should be managed as if born to an HBsAg-positive mother. The infant should receive both HepB and HBIG within 12 hours of birth. The mother should also be referred to their jurisdiction’s Perinatal Hepatitis B Prevention Program for case management to ensure that the infant receives timely prophylaxis and follow-up.