Hepatitis B surface antigen (HBsAg) testing is a cornerstone of global public health efforts to combat hepatitis B virus (HBV) infection. Its importance spans individual patient care, infection control, and public health strategy, making it one of the most critical diagnostic tools in modern medicine.
Firstly, the detection of HBsAg in the blood is the primary marker for diagnosing acute or chronic HBV infection. A positive result confirms that an individual is currently infected and can transmit the virus to others. This is crucial for initiating appropriate medical management. For acute infections, it allows for monitoring and supportive care to prevent severe complications like fulminant hepatitis. For chronic infections, an early diagnosis enables regular monitoring for liver damage (e.g., through ALT tests and fibrosis assessment), which guides decisions on when to start antiviral therapy to suppress the virus, thereby slowing the progression of liver disease, cirrhosis, and hepatocellular carcinoma (liver cancer).
Secondly, HBsAg testing is fundamental for preventing transmission. Identifying infected individuals allows for counseling on practices to prevent spreading the virus to close contacts and sexual partners. It is a vital component of prenatal screening; identifying HBsAg-positive pregnant women enables the administration of immunoprophylaxis (HBV vaccine and hepatitis B immune globulin) to their newborns immediately after birth. This intervention is over 90% effective in preventing perinatal transmission, which is a major route of establishing chronic infection globally.
Furthermore, HBsAg screening is essential for the safety of the blood supply and donated organs, and it is routinely used to test donors. It also plays a key role in screening high-risk populations and vaccinating susceptible individuals.
In summary, HBsAg testing is indispensable for diagnosis, enabling life-saving medical interventions, preventing new infections through targeted strategies, and ultimately reducing the global burden of chronic liver disease and cancer caused by HBV.
Post time: Sep-10-2025