Quantitative Assay of Hepatitis B Surface Antigen in Serum or Plasma Using Laurell Electrophoresis

Hepatitis B virus (HBV) leads to an overexpression of its surface antigen (HBsAg) in the infected hepatocytes. HBsAg is constitutively secreted as pleomorphic particles, predominantly spherical and partly filamentous. Their diameter appears in negatively stained electron micrographs as approx 20 nm. HBsAg typically reaches serum concentrations between 30 and 100 μg/mL during the incubation phase before acute hepatitis B; in immunotolerant hepatitis B e antigen (HBeAg)-positive HBV carriers and immunosuppressed carriers, HBsAg reaches serum concentrations up to 1000 μg/mL, corresponding to 2�10¹³ or 2�10¹⁴ particles/mL, respectively (1 ). Ahigh HBsAg concentration reflects both a large number of HBsAg-expressing cells and a low elimination rate of HBsAg.