Diagnostic significance of quantitative determination of hepatitis B surface antigen in acute and chronic hepatitis B infection.

HBsAg was determined quantitatively by radioimmunoassay and by Laurell electrophoresis in sera of 90 patients with acute hepatitis B, 57 patients with chronic hepatitis B, and 154 HBsAg positive blood donors. Of 55 patients with clearance of HBsAg from the circulation within six months, 54 (98%) showed an at least 50% reduction in concentration within 16 days. All 55 patients had such a decrease within 20 days. No such decrease was found in seven patients with acute hepatitis B who became HBsAg carriers. Therefore, quantitative HBsAg concentration in paired sera seems to be a reliable and early prognostic marker in acute hepatitis B. In patients with clearance of HBsAg most of the antigen is already present in the circulation at hospitalization and is eliminated with a mean half-life of 8.8 days. Patients with chronic hepatitis exhibit on average nearly the same HBsAg concentration (about 40,000 ng/ml) as patients with acute hepatitis B at hospitalization (about 39,000 ng/ml) and HBsAg positive blood donors on average a lower HBsAg concentration (about 8,000 ng/ml).