NEW YORK (GenomeWeb) ­– Quest Diagnostics has launched a new laboratory-developed assay to quantify hepatitis B surface antigen (HBsAg). Although quantitative HBsAg tests are widely used outside of the US, the test is the first to be offered stateside, potentially improving decision making for US physicians treating chronic HBV.

Hepatitis B virus infection, which affects up to 2.2 million people in the US, is typically detected and tracked in three ways: using viral DNA and two different viral surface proteins — HBsAg, and a surface protein called "e antigen," or HBeAg.