Medical Diagnosis Exams

The hepatitis B surface antigen, a polypeptide of varying size, is a component of the external envelope of the hepatitis B virus particle (HBV).

The detection of HBsAg in human serum or plasma indicates an infection by the hepatitis B virus. HBsAg is the first immunological marker and is generally present some days or weeks before clinical symptoms begin to appear.

HBsAg is observed in persons with acute and chronic hepatitis B infections. HBsAg tests are used within the scope of diagnostic procedures to identify persons infected with HBV and to prevent the transmission of the hepatitis B virus by blood and blood products.

HBsAg tests are also used to monitor the course of the disease in persons with acute or chronic HBV infections and if necessary, to check the efficacy of an antiviral therapy.

In addition, HBsAg tests are recommended as part of prenatal care, in order to be able to initiate suitable measures for preventing as far as possible the transmission of an HBV infection to the newborn child.