Hepatitis B Surface Antigen (HBsAg) Test

Know More About This Test

The HBsAg (Hepatitis B Surface Antigen) test detects the presence of Hepatitis B surface antigen in the blood, indicating active HBV infection. The Optical Density (OD) method improves test sensitivity. This test is used in screening and diagnosis and serves as a critical public health marker for identifying carriers and preventing transmission.

Why Is This Test Recommended?

HBsAg testing is recommended for screening for hepatitis B, blood donor testing, antenatal screening during pregnancy, pre-surgical evaluation, and monitoring known HBV cases. It is essential when symptoms like jaundice, fatigue, dark urine, abdominal pain, or history of exposure to infected blood are present.

What Do the Results Indicate?

Positive results indicate active infection, meaning the virus is in the bloodstream. Persistence for more than 6 months indicates chronic infection. Negative results mean no active infection. The antigen disappears with recovery, and vaccinated individuals remain negative. Further tests assess infectivity and disease progression, though HBsAg does not measure disease severity.

How Is the Test Performed and Prepared For?

A simple blood draw is performed. No fasting is required. The test is safe and quick, with results usually available within 24 hours. Inform your doctor about vaccination history before the test.

Frequently Asked Questions (FAQs)

Does positive mean lifelong infection?

Not always; some people clear the infection naturally within 6 months (acute infection), while others develop chronic infection requiring long-term management.

Can vaccine cause positivity?

No; hepatitis B vaccination does not cause HBsAg positivity as the vaccine contains only surface antigen protein, not the live virus.

Is it curable?

Manageable; while acute hepatitis B can resolve on its own, chronic infection is not curable but can be effectively managed with antiviral medications.

Is repeat testing required?

Yes; repeat testing is essential to monitor infection status, assess chronicity, evaluate treatment response, and check for viral clearance.

Is it contagious?

Yes; hepatitis B is highly contagious and spreads through blood, body fluids, unprotected sex, and from mother to child during birth.