Hepatitis B Surface Antigen (HBs Ag) analysis is a reliable test used to detect the presence of the Hepatitis B virus surface antigen in the blood. The presence of this antigen indicates an active infection with the virus, meaning the person could potentially transmit the infection to others. This test is one of the key examinations for diagnosing Hepatitis B and can help determine the stage of the infection, whether acute or chronic. It is recommended for individuals at risk of infection, such as healthcare workers, those living with an infected person, or those experiencing symptoms of hepatitis. The test is an important tool for guiding treatment decisions and monitoring liver health.