Hepatitis B (HBV) - sAg
HBsAg is a marker of HBV infection, indicating the presence of the virus. Quantitative detection monitors changes in the condition and is strongly positively correlated with HBV DNA. The level of HBsAg reflects viral replication and infectivity. In HBeAg positive carriers, high levels of HBsAg and HBV DNA indicate active replication. HBsAg testing is used for diagnosis, monitoring disease progression, assessing treatment response, and evaluating the efficacy of new drugs.