Hepatitis B Antigen - Infection
The Hepatitis B Antigen (HBsAg) Test detects the Hepatitis B surface antigen in your blood. A positive result means you may have an active Hepatitis B infection, which could be acute (recent) or chronic (long-term). This test helps determine if you currently have the virus and if you may be able to spread it to others. Hepatitis B is a virus that affects the liver and spreads through blood and bodily fluids. Testing is important for people with symptoms, those at higher risk, and individuals needing screening for work, travel, or medical procedures.
Test details
Sample type
Blood
Time of day
No Specific Time Needed
Fasting required
No
Results timeframe
Within 7 days
Preparation
Do not have this test performed if you have had the Hepatitis B vaccination in the last 30 days.
What's measured in this test
Hepatitis B Antigen
Detects current hepatitis B infection.
Common reasons for testing
- Checking for an active Hepatitis B infection – Determines if you currently have the virus and can spread it to others.
- Unexplained liver symptoms – Helps investigate jaundice (yellowing of the skin), fatigue, nausea, or abnormal liver function tests.
- Screening before medical procedures – Required before surgery, organ donation, or some medical treatments.
- Exposure to Hepatitis B – Recommended if you have been in contact with someone who has Hepatitis B or if you share needles or have unprotected sex.