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Biomarker

HBsAg

Hepatitis B surface antigen

A hepatitis B virus surface protein; its presence indicates current HBV infection.

Overview

EXPLORE BY LEVEL

is a piece of the hepatitis B . Finding it in blood means the is present now.

Quick Facts

AT A GLANCE
MeasuresA protein on the surface of hepatitis B virus
CategoryViral antigen · HBV serology
HBV panelsIn CDC's initial triple panel and the older five-marker panel
Interpretation limitHBsAg shows current infection but does not by itself distinguish acute from chronic infection.

Follow the Connections

See how HBsAg links to other biological records.

Open network
OrganismHepatitis B virusantigen ofBiomarkerAnti-HBsantibody toDiseaseHepatitis Bmarker for
All 3 Structured Connections
HBsAg · BiomarkerANTIGEN OF →Hepatitis B virus · Organism
Anti-HBs · BiomarkerANTIBODY TO →HBsAg · Biomarker
HBsAg · BiomarkerMARKER FOR →Hepatitis B · Disease

Recommended Reading

Trusted references for learning more about HBsAg.

guideClinical Testing and Diagnosis for Hepatitis BCenters for Disease Control and Prevention guideHepatitis TestingMedlinePlus Medical Tests guideScreening and Testing for Hepatitis B Virus Infection: CDC Recommendations — United States, 2023MMWR Recommendations and Reports
Research Claims

HBsAg shows current infection but does not by itself distinguish acute from chronic infection.

HBsAg is one of the three markers in CDC's initial triple panel. Distinguishing acute from chronic infection requires additional markers such as IgM anti-HBc and follow-up over time.