The Hepatitis B Envelope Antigen (HBeAg) test is a blood test that detects the presence of the Hepatitis B virus envelope antigen in the blood. The HBeAg is a protein that is present on the surface of the virus and is involved in viral replication. The test is used to diagnose and monitor the progression of Hepatitis B infection. A positive HBeAg test result indicates that the virus is actively replicating in the body and the person is highly infectious. The test is usually ordered for individuals who are suspected of having acute or chronic Hepatitis B infection, as well as for pregnant women who are carriers of the virus, to assess the risk of mother-to-child transmission. A negative HBeAg test result indicates that the virus is in a less active stage and the person is less infectious. The HBeAg test is an important tool in the management of Hepatitis B and is often performed alongside other liver function tests, viral load tests, and HBeAg antibody tests to assess the disease activity and treatment response.