Hepatitis B Surface Antigen (HBsAg)

The Hepatitis B Surface Antigen (HBsAg) is a screening test to detect the presence of hepatitis B surface antigen (HBsAg) in the blood. This test helps detect recent infection, previous exposure to Hepatitis B virus (HBV) and helps monitor treatment response. 

Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). It can spread through contact with infected body fluids like blood, saliva, vaginal fluids and semen. It can also be passed from a mother to her baby during childbirth.

HBsAg is a protein on the surface of HBV that can be detected in high levels in serum during acute or chronic HBV infection. This antigen can be found in your blood within several weeks after the infection starts. It is one of the earliest markers of a hepatitis B infection. Most infected individuals do not exhibit any symptoms following initial infection. However, some common symptoms are fever, nausea, vomiting, loss of appetite, stomach pain, joint pain, dark-colored urine, light-colored stool, and the yellowing of skin and eyes (jaundice). The presence of HBsAg indicates that the person is infectious. Continued persistence of HBsAg may be seen in chronic carriers as well as patients with chronic hepatitis B.

The Hepatitis B Surface Antigen (HBsAg) test is typically advised for individuals who show symptoms of acute hepatitis. Additionally, doctors may advise this test for individuals at higher risk of HBV infection, including those with a history of unprotected intercourse with multiple partners, injection drug users, healthcare workers exposed to blood or body fluids, as a part of routine checkups, preoperative and pre employment check ups, prior to vaccination and in infants born to mothers infected with HBV. Routine screening for HBsAg is also recommended for pregnant women to prevent mother-to-child transmission. Early detection through the Hepatitis B Surface Antigen (HBsAg) test enables prompt intervention, including antiviral therapy, to manage the infection effectively and reduce the risk of complications such as liver cirrhosis or cancer.

No special preparation is needed for this test. You may eat and drink as per your daily routine. However, inform the doctor about any medications that you are taking or if you have a history of any bleeding disorders or recent vaccinations, as these factors may influence the test results. Narrate your complete medical history to the doctor to help them correlate your clinical and laboratory findings. 

Lab test results may vary across laboratories. The Hepatitis B Surface Antigen (HBsAg) test utilizes an automated chemiluminescence immunoassay technology for the detection of HBsAg. The technology (CMIA/CLIA) can vary based on different machines available in different locations.

Lab test results require expert interpretation; therefore, never self-medicate at home solely based on these results and always consult a doctor for proper understanding of the test results.