Clinical and Interpretive

This test is used to identify previous exposure to hepatitis B virus and determine adequate immunity from hepatitis B vaccination.

Hepatitis B virus (HBV) infection, also known as serum hepatitis, is endemic throughout the world. The infection is spread primarily through blood transfusion or percutaneous contact with infected blood products, such as sharing of needles among injection drug users. The virus is also found in virtually every type of human body fluid and has been known to be spread through oral and genital contact. HBV can be transmitted from mother to child during delivery through contact with blood and vaginal secretions, but is not commonly transmitted via the transplacental route.

The incubation period for HBV infection averages 60 to 90 days (range of 45-180 days). Common symptoms include malaise, fever, gastroenteritis, and jaundice (icterus). After acute infection, HBV infection becomes chronic in 30% to 90% of infected children <5 years of age and in 5% to 10% of infected individuals ≥5 years of age. Some of these chronic carriers are asymptomatic, while others progress to chronic liver disease, including cirrhosis and hepatocellular carcinoma.

Hepatitis B surface antigen (HBsAg) is the first serologic marker, appearing in the serum 6 to 16 weeks following HBV infection. In acute cases, HBsAg usually disappears 1 to 2 months after the onset of symptoms with the appearance of hepatitis B surface antibody (anti-HBs). Anti-HBs also appears as the immune response following hepatitis B vaccination.

A positive result indicates recovery from acute or chronic hepatitis B virus (HBV) infection, or acquired immunity from HBV vaccination. This assay does not differentiate between a vaccine-induced immune response and an immune response induced by infection with HBV. A positive total anti-hepatitis B core (anti-HBc) result would indicate that the hepatitis B surface antibody (anti-HBs) response is due to past HBV infection.

Positive results (quantitative hepatitis B surface antibody [anti-HBs] levels of ≥12.0 mIU/mL) indicate adequate immunity to hepatitis B from past hepatitis B or HBV vaccination. After receiving a primary HBV vaccine series, individuals with anti-HBs levels of 12 mIU/mL or greater are considered protected from hepatitis B in accordance with the CDC guideline.

A negative result (quantitative anti-HBs level of <5.0 mIU/mL) indicates a lack of recovery from acute or chronic hepatitis B or inadequate immune response to HBV vaccination. The U.S. Advisory Committee on Immunization Practices does not recommend more than 2 HBV vaccine series in nonresponders.

Indeterminate results (quantitative anti-HBs levels in the range from ≥5 to <12 mIU/mL) indicate inability to determine if anti-HBs is present at levels consistent with recovery or immunity. Repeat testing is recommended in 1 to 3 months.Passively acquired hepatitis B surface antibody (anti-HBs) (ie, transfusion of Individuals who have received blood component therapies (eg, whole blood), plasma, or intravenous immunoglobulin infusion in the previous 3 to 6 months may have false-positive anti-HBs results due to passive transfer of anti-HBs present in these products.

Anti-HBs levels from past hepatitis B or HBV vaccination may fall below detectable levels over time.

A positive anti-HBs result does not exclude infection by another hepatitis virus.