How HBsAg Can Be Negative By Ayurvedic Herbs? What is HBsAg? HBsAg is a surface antigen for Hepatitis- B virus. It is also known as Australia antigen. Detection of HBs Ag signifies that you are suffering from Hepatitis-B infection. What is Hepatitis-B? Viral infections are very common now a days. Hepatitis is also one of them. “Hepatitis” comprises of two words “Hepat” and “It is”- “Hepat” stands for Liver and It is stands for inflammation, so Hepatitis stands for inflammation