From the Guidelines
A positive hepatitis B surface antigen (HBsAg) result indicates an active hepatitis B virus infection, which can be either acute or chronic, and requires further testing and management to prevent transmission and potential liver damage. This test detects the presence of the viral protein that appears on the surface of the hepatitis B virus, and when this antigen is found in the blood, it indicates the virus is present and can be transmitted to others 1. The infection could be acute (recent infection) or chronic (long-term infection lasting more than 6 months). If a person tests positive for HBsAg, they should see a healthcare provider for additional testing to determine if the infection is acute or chronic, assess liver function, and determine appropriate management.
Further tests typically include:
- Hepatitis B e-antigen (HBeAg)
- Hepatitis B e-antibody (anti-HBe)
- Hepatitis B core antibody (anti-HBc)
- Viral load testing Treatment depends on whether the infection is acute or chronic and may include antiviral medications like entecavir, tenofovir, or pegylated interferon 1. People with positive HBsAg should avoid alcohol, inform sexual partners, and take precautions to prevent transmission through blood or body fluids. Regular monitoring of liver function is essential as chronic hepatitis B can lead to liver damage, cirrhosis, or liver cancer over time. According to the most recent guidelines, a confirmed HBsAg-positive result indicates active HBV infection, and all HBsAg-positive persons should be considered infectious 1.
From the Research
Hepatitis B Surface Antigen (HBsAg)
- A positive hepatitis B surface antigen (HBsAg) test result indicates that a person is infected with hepatitis B virus (HBV) 2, 3, 4, 5, 6.
- The presence of HBsAg in the blood suggests that the person is contagious and can transmit the virus to others 2, 3, 4, 5, 6.
Interpretation of HBsAg Test Results
- A positive HBsAg test result can indicate either an acute or chronic HBV infection 2, 3, 4, 5, 6.
- The level of HBsAg in the blood can also provide information about the severity of the infection and the effectiveness of treatment 4, 5, 6.
- A decrease in HBsAg levels over time can indicate a response to treatment, while an increase in levels can suggest a worsening of the infection 4, 5, 6.
Clinical Significance of HBsAg
- The presence of HBsAg is a key factor in determining the risk of HBV transmission and the need for treatment 2, 3, 4, 5, 6.
- HBsAg levels can also be used to monitor the effectiveness of treatment and predict the risk of relapse after treatment is stopped 5, 6.
- A combination of HBsAg levels and other factors, such as age and HBV genotype, can be used to guide treatment decisions and predict outcomes 5, 6.