HBsAgpositive

HBsAgpositive (often written HBsAg-positive) refers to the presence of hepatitis B surface antigen (HBsAg) in a person’s blood. HBsAg is a protein on the outer surface of the hepatitis B virus (HBV) and is used clinically as a primary marker of active HBV infection. Detection of HBsAg typically indicates current infection, which may be acute or chronic depending on duration and additional test results.

Clinically, HBsAg is measured by immunoassays; persistent positivity for more than six months is the usual criterion for chronic hepatitis B. Additional serologic markers—such as anti-HBs, anti-HBc (IgM and IgG), and HBeAg—and molecular tests for HBV DNA help distinguish acute from chronic infection, assess infectivity, and guide management. HBeAg positivity commonly correlates with higher viral replication and greater transmissibility.

HBsAg-positive individuals can transmit HBV through blood, sexual contact, and perinatal routes. Public health responses include notification, contact tracing, counseling about transmission precautions, and offering vaccination to susceptible contacts. Many HBsAg-positive people remain asymptomatic but require monitoring for liver inflammation and long-term complications such as cirrhosis and hepatocellular carcinoma; surveillance and treatment decisions are based on liver function tests, HBV DNA levels, and imaging. Vaccination induces protective anti-HBs and prevents infection; false-positive HBsAg results are uncommon but may warrant repeat testing or confirmatory molecular assays.