Hepatitis B surface antigen (HBsAg) is a crucial protein that resides on the surface of the Hepatitis B virus (HBV), serving as a marker that enables our immune system to identify and combat the virus. The qualitative HBsAg test, a blood test, is employed to ascertain the presence of this antigen. A positive test result indicates an ongoing Hepatitis B infection, while a negative result suggests the absence of current infection. This test holds immense significance due to the potential of untreated Hepatitis B to cause severe liver damage. Early detection through the qualitative HBsAg test allows healthcare professionals to promptly initiate treatment if necessary, thereby averting the progression of the infection and minimizing the risk of liver-related complications.