A 35-year-old male patient presented with history of jaundice for 15 days. The onset was preceded by a prodromal illness. His serum tested positive for HbsAg. A clinical diagnosis of acute hepatitis B was made. What should be the next best confirmatory investigation?

Since IgM anti-HBcAg is not given in the choices, HBeAg, appears concurrently with or sholy after HBsAg. Its appearance coincides with high levels of virus replication & reflects presence of circulating intact virions and detectable HBV DNA In self-limited HBV infections, HBeAg becomes undetectable sholy after peak elevations in aminotransferase activity, before the disappearance of HBsAg, and anti-HBe then becomes detectable, coinciding with a period of relatively lower infectivity. Its principal clinical usefulness is as an indicator of relative infectivity.