A simple finger-prick blood test to check for a current infection of hepatitis B.
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Infection
Hepatitis B surface antigen
Learn more
The hepatitis B surface antigen (HBsAg) is a protein on the surface of the hepatitis B virus, present in the blood during a hepatitis B virus infection. Checking for this surface antigen helps to identify acute and chronic HBV infections. Positive surface antigen meaning the virus is present and that the individual is infectious.
Special instructions
How to prepare for your test
Prepare for your Hepatitis B Surface Antigen Blood Test by following these instructions. If there is a chance that you have been exposed to HIV, hepatitis B or C then please let us know how long before taking your sample this occurred. Your sample should be taken 4 weeks after any hepatitis B exposure. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.
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FAQs
What is hep B?
Hepatitis B is an infection caused by the hepatitis B virus (HBV), which causes inflammation and enlargement of the liver. HBV infections can vary from a mild form that lasts a few weeks to a chronic form that can cause lasting liver damage. HBV is spread through contact with blood or other body fluids from an infected person. Exposure can occur through sharing needles or through unprotected sex. People who live in or travel to areas where HBV is prevalent are at greater risk. It is possible for pregnant women to pass the infection to their babies, usually during or after birth.
What can I learn from this test?
Hepatitis B Surface Antigen (HBsAg) can be detected in the blood on average around four weeks after exposure to HBV. HBV is a DNA virus that consists of a core particle and a surrounding envelope. The envelope of the virus contains the surface antigen (HBsAg). Therefore, our test looks for the presence of HBsAg to identify a hepatitis infection.
Who is the HBV antigen test for?
Our Hepatitis B Surface Antigen Blood Test is for people who think they may have an active current infection of hepatitis B. It does not test for antibodies, so it will not tell you whether you have immunity to hepatitis B.