Hepatitis Bs (Surface) Antigen
What is HBsAg?
Hepatitis B Surface Antigen (HBsAg), also known as Australia antigen is present on the surface of the Hepatitis B virus (HBV). This test detects the presence of Hepatitis B Surface Antigen (HBsAg) in the blood.
Why is HBsAg done?
To detect Hepatitis B virus infection in patients having symptoms suggestive of Hepatitis
To screen for Hepatitis B infection following accidental exposure to HBV e.g. in healthcare workers. Repeat testing is recommended after 6 weeks post exposure
To screen for Hepatitis B infection in individuals who are at risk of acquiring infection like IV drug users, sex workers, hemodialysis patients, prisoners, etc.
To screen for Hepatitis B infection during pregnancy to prevent transmission of infection from mother to child
What does HBsAg Measure?
HBsAg test detects the presence or absence of Hepatitis B Surface Antigen (HBsAg) in the blood.
Hepatitis B virus is one of the five main hepatitis viruses, referred to as types A, B, C, D and E and is the causative agent of Hepatitis B (infection in the liver). Hepatitis B Surface Antigen (HBsAg) is present on the surface of the Hepatitis B virus (HBV). HBsAg is present in the blood of patients with viral hepatitis B (with or without clinical symptoms).
HBsAg is the first marker appearing in the blood at 6 to 16 weeks following exposure to HBV. In most cases after an acute infection, this virus clears up on its own in 1 to 2 months after the onset of symptoms. But in some people, the virus does not go away and results in chronic infection which over the years may lead to liver damage (scarring or cirrhosis) or liver cancer. Persistence of HBsAg for more than 6 months indicates the development of either a chronic carrier state or chronic HBV infection.
Interpreting HBsAg results
A "Reactive" or "Positive" HBsAg test result means that the person is infected with Hepatitis B virus. If a person tests “positive,” then further testing is required to determine if this is a new “acute” infection or a “chronic” Hepatitis B infection or chronic HBV carrier state.
A "Non-reactive" or "Negative" HBsAg test result means that the person is not infected with Hepatitis B virus.
Answers to Patient Concerns & Frequently Asked Questions (FAQs) about HBsAg
Frequently Asked Questions about Hepatitis Bs (Surface) Antigen