Hepatitis B Surface Antigen
The Hepatitis B Surface Antigen (HBsAg) test detects proteins on the surface of the hepatitis B virus. A positive result indicates an active hepatitis B infection.
Category: Infectious Disease
Also known as: hbsag, hepatitis b surface antigen, hbs ag, hep b surface antigen, hepatitis b antigen, hepatitis b površinski antigen
Reference range: 0–0.05 IU/mL (Source: ABIM)
Standard unit: IU/mL
High values may indicate
A positive (reactive) HBsAg result indicates current hepatitis B infection, which may be acute or chronic.
Low values may indicate
A negative (non-reactive) HBsAg result means no active hepatitis B infection is detected.
Frequently asked questions
- What is a normal Hepatitis B Surface Antigen level?
- A typical reference range for Hepatitis B Surface Antigen is 0–0.05 IU/mL (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is Hepatitis B Surface Antigen measured in?
- Hepatitis B Surface Antigen is most commonly reported in IU/mL. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do Hepatitis B Surface Antigen reference ranges come from?
- BloodId uses ABIM standard reference ranges and educational information from MedlinePlus (see our methodology). Reference ranges still vary by lab, age, and sex, so always compare against your own report.
- Can I track Hepatitis B Surface Antigen over time?
- Yes. Upload results from any lab and BloodId charts your Hepatitis B Surface Antigen over time against its reference range, so you can see whether the trend is rising, falling, or stable.
Related biomarkers
Source: MedlinePlus, U.S. National Library of Medicine
Analyze your Hepatitis B Surface Antigen with AI
Chart your Hepatitis B Surface Antigen over time
Track your Hepatitis B Surface Antigen over time with BloodId