Hepatitis Bs Antigen (HBsAg) for Cadaveric or Hemolyzed Specimens, Serum
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Hepatitis B virus (HBV) is endemic throughout the world. The infection is spread primarily through percutaneous contact with infected blood products (eg, blood transfusion, sharing of needles by intravenous drug addicts). The virus is also found in various human body fluids, and it is known to be spread through oral and genital contacts. HBV can be transmitted from mother to child during delivery through contact with blood and vaginal secretions, but it is not commonly transmitted transplacentally.
Hepatitis B surface antigen (HBsAg) is the first serologic marker appearing in the serum at 6 to 16 weeks following HBV infection. In acute infection, HBsAg usually disappears in 1 to 2 months after the onset of symptoms. Persistence of HBsAg for >6 months indicates development of either a chronic carrier or chronic HBV infection.
Testing cadaveric and hemolyzed blood specimens for hepatitis B surface antigen; FDA-licensed for use with hemolyzed specimens
Diagnosis of acute, recent (<6 month duration), or chronic hepatitis B infection; determination of chronic hepatitis B carrier status
A positive result (reactive screening and confirmed positive by neutralization test; see Method Description) is indicative of acute or chronic hepatitis B virus (HBV) infection, or chronic HBV carrier state.
A positive (confirmed) neutralization test result is considered the definitive test result for hepatitis B surface antigen (HBsAg). Specimens that are reactive by the screening test but negative (not confirmed) by the neutralization test are likely to contain cross-reactive antibodies from other infectious or immunologic disorders. These unconfirmed HBsAg screening test results should be interpreted in conjunction with test results of other HBV serological markers (eg, anti-hepatitis B surface antibody, anti-hepatitis B core total antibody).
The presence of HBsAg is frequently associated with HBV infectivity, especially when accompanied by the presence of hepatitis Be antigen and/or HBV DNA.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test is not useful during the "window period" of acute hepatitis B virus (HBV) infection, (ie, after disappearance of hepatitis B surface antigen [HBsAg] and prior to appearance of anti-HBs antibody). Testing for acute hepatitis B virus infection should also include anti-hepatitis B core IgM antibody.
Positive HBsAg test results should be reported by the health care provider to the State Department of Health, as required by law in some states.
Individuals, especially neonates and children, who recently received hepatitis B vaccination may have transient-positive HBsAg test results because of the large dose of HBsAg used in the vaccine relative to the individual's body mass.
Performance characteristics have not been established for the following specimen characteristics:
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Servoss JC, Friedman LS: Serologic and molecular diagnosis of hepatitis B virus. Clin Liver Dis 2004;8:267-281
2. Badur S, Akgun A: Diagnosis of hepatitis B infections and monitoring of treatment. J Clin Virol 2001 Jun;21(3):229-237