Hepatitis B Surface Antigen
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.
What might a high result mean?
A positive result for HBsAg indicates active hepatitis B infection, this means that there is a risk you can spread the hepatitis B virus to others.