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Hepatitis B Surface Antigen

HBsAg Australian Antigen
Serum (SST) Positive/Negative

About this test

Outer envelope protein of hepatitis B virus. First marker to appear after infection (4–12 weeks). Persistence >6 months defines chronic HBV infection.

Reference Ranges

Sex Age Range Notes
All All ages See notes Negative (non-reactive) is normal

Clinical Interpretation

Low / Decreased
Negative — acute HBV or chronic HBV very unlikely (if negative, check anti-HBc).
High / Increased
Positive — acute or chronic HBV infection. Refer for virology work-up and treatment assessment.
Specimen
Serum (SST)
Reporting Unit
Positive/Negative
Category
🦠 Microbiology

⚠ Clinical Note
Reference ranges are indicative. Always interpret results in the context of the individual patient and local laboratory reference intervals, which may vary.